Flv2mp3 virus? What flv2mp3.by shows in 2026 and how to remove the ads
Flv2mp3 was a free YouTube-to-MP3 converter that our 2021 guide classed as ad-supported adware, with a page full of ads and a notification prompt. In our October 2026 test flv2mp3.by showed a Russian-language blog instead of a converter, so what you may need to remove is the old program, an add-on or a notification permission, not the website.
Facts checked October 6, 2026. Removal steps tested on Windows 11 (26H2) and checked against Microsoft's and the browser makers' current documentation.
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Flv2mp3 ads: summary
| Type | YouTube-to-MP3 converter: a web page and a Windows program listed on a download portal; ad-supported; our 2021 guide called it adware and a potentially unwanted program |
|---|---|
| Risk | Low to medium: the site now shows a blog and nothing was seen on one visit; the old program, an add-on or an allowed notification can stay on your PC |
| Symptoms | A converter you do not remember in Installed apps or the extension list; flv2mp3.by in the Notifications list; more ads on sites you visit; new tabs opening by themselves |
| How to get rid of it | Uninstall the program in Installed apps, remove the extension, remove flv2mp3.by from the Notifications list, clear site data (steps below); scan only if you ran a file from an ad |
| Our check (6 October 2026) | A Russian-language blog (FLV Master); no converter, ads, redirect, notification request, pop-up or service worker on one visit; only Google Fonts contacted |
| Running since / first seen | A CNET listing for FLV2MP3 dated 24 April 2009 (cflv2mp3.com); the domain's registration date is not available (no RDAP for .by) |
| Removal | Scan the PC with security software to find and remove the malware and anything installed with it. Fortect scans Windows for malware and repairs the system files and settings it damaged. Remove it nowTo use the full-featured product, you have to purchase a license for Fortect. The scan is free. |
Show 12 more facts
| First reported by us | 4 June 2021 |
|---|---|
| Installed on the PC | Nothing by visiting the site; only the program or an add-on, if you added them yourself, put anything on the PC |
| Microsoft detection | No Microsoft detection name is known: we found none for the web page or for the Windows program |
| Evidence | Our test of flv2mp3.by and our 2021 captures; no detection names for 2026 |
| Name | Flv2mp3 |
| Domains | flv2mp3.by |
| Ads shown as | Redirects through ad pages |
| Browsers | Chrome, Edge and Firefox |
| First seen | 4 June 2021 |
| Distribution | Typically ad scripts on free streaming, file-hosting and adult sites, typo domains and hacked websites |
| Damage | Redirects to scam pages, fake updates and tech support scams |
| Facts checked | 6 October 2026 |
Facts checked on 6 October 2026 against our own test of flv2mp3.by in desktop Chromium from Europe: one visit, no clicks. We did not install the Windows program or any add-on, and the .by registry has no RDAP record, so the domain's age and owner are not confirmed.
What Flv2mp3 is and how it worked
Flv2mp3 was a web page that turned a YouTube link into an audio or video file, and our 2021 guide linked it to a Windows program of the same name on CNET's download site. In October 2026 flv2mp3.by no longer shows a converter, so most of this page is about what the old one may have left on your PC and in your browser.
- 1
Paste a link
You copied the address of a YouTube video into the box on the converter page.
- 2
Pick a format
The page offered MP3, MP4, MP4 HD, AVI and AVI HD (as the buttons in our 2021 picture show).
- 3
Get a file
A real conversion ends with a media file. A program (
.exe), a browser add-on or a prompt to allow notifications is not part of it.
- Forms in 2021
- A web page at flv2mp3.by, and a Windows program called FLV2MP3 on CNET's download site (the listing names the web address cflv2mp3.com, so we cannot confirm one owner)
- Detection
- Our 2021 guide called it a potentially unwanted program (PUP) and adware; we have no detection names for it in 2026
- Paid for by
- Advertising: the 2021 converter page carried ad tiles, some for chat and dating offers
- Data it listed
- The privacy policy in our 2021 picture lists your IP address, country, browser, referring URL, operating system and request times
The name comes from FLV, the video format of Adobe Flash. Adobe stopped supporting Flash Player after 31 December 2020 and blocked Flash content from running from 12 January 2021, so a tool built around FLV files is a leftover of an older web. Free converters like this one earn from ads and from being bundled with other software, which is why the old guide spent most of its words on ads and installers.
Is Flv2mp3 ads dangerous?
Our test on 6 October 2026
We opened flv2mp3.by the way a visitor does: a clean desktop Chromium profile in Europe. The address answers, but it is no longer a converter: it is a Russian-language blog. That is one visit, so it tells you what the site showed us, not what it never does.
flv2mp3.by · desktop Chromium · Europe · 6 October 2026
- The converter is goneThe page loaded (HTTP 200) with the title
ФЛВ Мастер — главная(FLV Master, home): a blog of articles about servers, analytics and infrastructure for video and music download services. We saw no converter box and no download button on the page. The old converter path/en2/, shown in our 2021 pictures, now ends on the same home page. - Notification requestNone on this visit. The browser showed no permission prompt, although the 2021 converter page did (see the pictures further down).
- Redirects and pop-upsNone on this visit: the address stayed
https://flv2mp3.by/and no new window opened. - Ad networks and service workerNo ad network and no service worker seen, so nothing stayed in the browser after we left.
- Hosts contactedOnly
fonts.googleapis.comandfonts.gstatic.com(Google Fonts) besides the site itself. - Who runs itWe cannot tell whether the owner is the same as in 2021. The .by registry offers no public RDAP record we could query, so the domain's registration date is unknown to us.
- Not testedWe did not run the Windows program or any browser add-on. We ran one visit, from Europe, without clicking anything. Adware often changes by country, device, referrer and time, or waits for a click or a second visit, so another visitor may see something else.
Nothing on this one visit On this single visit the site showed no ads, redirect or notification prompt, and it is not the converter our 2021 guide described. That does not clear the name: the old program, an extension or a notification permission from 2021 can still be on your PC.
What changed since our 2021 report
April 2009
A listing on CNET's download site
The CNET page in our 2021 picture describes FLV2MP3 as a tool "which allows you to convert your favourite FLV-files into MP3 files", version 1.0 for Windows, added 04/24/09, with 40,793 downloads in total and 12 in the last week. Our 2021 guide named CNET (and Softonic) as places where the program could be found and where unwanted software spreads, next to software bundling.
31 December 2020
Adobe ends Flash Player
FLV is Flash's video format. Adobe stopped supporting Flash Player after this date and blocked Flash content from running from 12 January 2021; it also warns that Flash Player copies on third-party sites are a common source of malware.
4 June 2021
Our report: a converter with ads
We described a converter with its own domain and a download link on CNET, offering to turn a YouTube link into MP3, MP4 HD, AVI or AVI HD. Our 2021 guide called it adware and a potentially unwanted program.
The converter page and the CNET download-site listing for FLV2MP3, as shown in our 2021 report. The listing names the web address cflv2mp3.com. 2021
Ads and a notification prompt on the page
Under the converter box the page carried three ad tiles; two were for chat and dating offers, which our 2021 guide described as chat with "hot girls". Chrome showed a prompt that the site "wants to show notifications", with Block and Allow. The page's own text read: "If you are tired of low speed and complicated conversion processes, we are ready to help you with alternative decision! Choose our free YouTube to mp3 online downloader. You need to make two simple steps and your favourite YouTube videos are already on your chosen device via our easy to use online converter."
The converter page in 2021: a box for a link, buttons for AVI HD, AVI, MP4 HD, MP4 and MP3, a Chrome prompt asking to show notifications, and three ad tiles at the bottom, two of them for chat and dating offers. 2021
The privacy policy
The policy said that when you use the search function, convert files or download files, your IP address, country of origin and other non-personal information about your computer or device (web requests, browser type and language, referring URL, operating system, date and time of requests) may be recorded. The list went on with usage information such as search terms, uploaded content, correspondence and cookies.
The privacy policy of the converter in 2021, with the same notification prompt and the start of its Data Collected list. June 2021
Last change to our guide
We did not update the guide again; its steps were for Windows 7 and 8, Internet Explorer and the old Edge.
October 2026
Our new check: a blog, no converter
flv2mp3.by now shows a Russian-language blog, with no ads, redirect or notification request on one visit. The domain's age cannot be checked: the .by registry has no RDAP service.
What to check on your PC and in your browser
Visiting a website installs nothing. What can stay on a PC is a program you downloaded, a browser add-on, or a notification permission you gave, so check those three.
| What you see | What it means |
|---|---|
| FLV2MP3 or another converter in Installed apps | The program from the CNET listing, or a similar converter. Remove it if you do not use it. |
flv2mp3.by in your browser's Notifications list | You clicked Allow on the 2021 prompt. Remove the entry so the site cannot use it. |
| A converter, "player" or downloader in your browser's extension list | An add-on the program or a bundled installer may have added. Remove it. |
| A converter entry in Startup apps | The program starting with Windows. Turn it off, then uninstall. |
| More ads on sites you visit often, or a browser that opens new tabs by itself | Possible adware effects. Ads alone do not prove Flv2mp3 is the cause; check the extension list. |
- 1
Turn off the startup entry
Press Ctrl + Shift + Esc, open Startup apps, right-click any converter entry you do not recognise and choose Disable.
- 2
Uninstall the program
Go to Settings > Apps > Installed apps (Windows 11) or Apps & features (Windows 10), find FLV2MP3 or a converter you do not remember, and choose Uninstall (Uninstall a program or app in Windows On uGetFix). If it says the program is running, end it in Task Manager first and try again.
- 3
Take back the notification permission
In Chrome open Settings > Privacy and security > Site settings > Notifications, find
flv2mp3.byunder the allowed sites and remove it. Edge, Firefox and Safari steps are below. - 4
Remove the add-ons
Use the steps for your browser below to remove any converter or downloader extension you did not install on purpose.
Remove every part, not only the visible one: a program uninstalled while its add-on or notification permission stays can bring the ads back.
The real risks, from most to least serious
Our 2026 visit found a blog, not a virus. These are the ways the old converter, its ads or its program could still hurt.
- High
Running a file that came from an ad or an installer
Fake updates, fake players and installers with extras are how adware, and now and then a trojan, reach a PC. Our 2021 guide warned about "Flash Player" and JavaScript updates offered by ads. Flash Player no longer exists, so any such update offer is false. Adobe says unauthorised copies of it are a common source of malware.
- Medium
A notification permission that was never removed
The 2021 converter page asked Chrome for permission to show notifications. If you clicked Allow, the permission stays in your browser until you remove it, and whoever controls that address can use it. The steps above show where to take it back.
- Medium
Ads that lead to deals and scams
The 2021 ads promoted apps, chat and dating offers and "beneficial-looking" deals. A click can end on a page that sells a useless service or asks for personal details. Ads on converter, torrent and adult-themed sites often come from networks that also sell space to criminals.
- Medium
Browsing details recorded for advertising
Our 2021 guide said the developers collect browsing information and use it for targeted ads and pay-per-click offers. The part of the policy we pictured lists IP address, country, browser, referring URL, system and request times, but does not show what it is used for. We could not find that policy on the site in 2026, so we could not re-read it.
- Medium
Bundled installs
Our 2021 guide said programs like this spread through download portals such as CNET and Softonic, and in software bundles where the Quick setup accepts extras for you.
- Low
Redirects
Our 2021 guide said adware can force redirects, sometimes to affiliate or even harmful pages. We saw no redirect from flv2mp3.by in 2026, so treat this as a possible effect of the old program, not as something we observed.
What the 2021 policy said it may record
- IP address
- Country
- Web requests
- Browser type and language
- Referring URL
- Operating system
- Date and time of requests
- Search terms
- Uploaded content
- Cookies
Adware earns from ads, so it wants to know what you view and click. If you also ran a file from an ad, see "If you clicked an ad or ran a file".
How to remove Flv2mp3 ads
How to stop the Flv2mp3 redirects
Work in this order and test a few links after each step, so you know which one was the cause.
Which browser shows the ads?
Take back the notification permission
Open Settings > Privacy and security > Site settings > Notifications, find
flv2mp3.byunder the sites allowed to send notifications, click the three dots and choose Remove (or Block).Remove extensions you do not recognise
Paste
chrome://extensionsinto the address bar and click Remove on anything you did not install yourself, especially video converters, downloaders and "search" or PDF helpers added recently.Full procedure with screenshots: Remove a browser extension
Clear the site data
Press Ctrl + Shift + Delete, choose All time, tick Cookies and other site data and Cached images and files, and click Delete data.
Reset Chrome
Open Settings > Reset settings > Restore settings to their original defaults and confirm with Reset settings. This resets the start page, search engine and pinned tabs and turns off extensions; bookmarks and saved passwords stay. To stop notifications after you close Chrome, also turn off Settings > System > Continue running background apps when Google Chrome is closed.
Full procedure with screenshots: Reset a browser and fix a hijacked search engine
Take back the notification permission
Open Settings > Cookies and site permissions > Notifications, find
flv2mp3.byin the allowed list and remove it.Remove extensions you do not recognise
Paste
edge://extensionsinto the address bar and click Remove under anything you did not install yourself.Full procedure with screenshots: Remove a browser extension
Clear the site data
Open Settings > Privacy, search, and services > Delete browsing data > Choose what to clear, set All time, tick Cookies and other site data and Cached images and files, and click Clear now.
Reset Edge
Open Settings > Reset settings > Restore settings to their default values and confirm with Reset. Extensions are turned off and the start page goes back to default; favourites, history and saved passwords stay. To stop notifications after you close Edge, turn off Settings > System and performance > Continue running background extensions and apps when Microsoft Edge is closed.
Full procedure with screenshots: Reset a browser and fix a hijacked search engine
Take back the notification permission
Open Settings > Privacy & Security, scroll to Permissions, click Settings next to Notifications, select
flv2mp3.byand choose Remove Website, then Save Changes.Remove add-ons you do not recognise
Paste
about:addonsinto the address bar, open Extensions, and choose Remove from the three-dot menu of anything you did not install yourself.Full procedure with screenshots: Remove a browser extension
Clear cookies and site data
Open Settings > Privacy & Security > Cookies and Site Data > Clear Data, tick both boxes and click Clear.
Refresh Firefox
Open the menu > Help > More troubleshooting information and click Refresh Firefox. Add-ons and custom settings are removed and the home page goes back to default; bookmarks, history and passwords stay.
Full procedure with screenshots: Reset a browser and fix a hijacked search engine
Take back the notification permission
Safari 18 and later on macOS: open Safari > Settings > Websites > Notifications, select
flv2mp3.by(or any site you do not recognise) and set it to Deny, or click Remove. Untick Allow websites to ask for permission to send notifications at the bottom so no site can ask again.Remove extensions you do not recognise
In Safari > Settings > Extensions, select anything you did not install yourself and click Uninstall.
Clear the site data
In Safari > Settings > Privacy > Manage Website Data, remove the site's data, or use History > Clear History > all history. To empty the cache as well, turn on Show features for web developers in Settings > Advanced and choose Develop > Empty Caches.
Check the Mac for apps from the ads
Ads also target Mac users with fake players and "cleaners". In Finder > Applications, move anything unknown to the Bin. In System Settings > General > Login Items & Extensions, remove unknown items. Then use Go > Go to Folder to check
/Library/LaunchAgents,~/Library/LaunchAgents,/Library/LaunchDaemonsand/Library/Application Supportfor folders and files with the same unknown names, and empty the Bin.
Then, whichever browser you use
Step 1: Scan the PC if you downloaded anything from the ads
Most people who only saw the notifications can skip this step. If a notification or the page it opened made you download or run a file, delete the file and run a full scan, then a Microsoft Defender Offline scan.
In Windows 11 and Windows 10 open Windows Security > Virus & threat protection > Scan options, select Microsoft Defender Antivirus (offline scan) and click Scan now. The PC restarts and the scan takes about 15 minutes, so save your work first.
Windows 11: Windows Security > Virus & threat protection > Scan options. Full procedure with screenshots: Run a Microsoft Defender Offline scan
After removal: keep the ads from coming back
If you clicked an ad or ran a file
Removing the program, the add-on and the notification permission is enough if you only saw ads. If an ad or an installer made you download or run something, do these three things as well.
- 1
Remove what was installed that day
Go to Settings > Apps > Installed apps (Windows 11) or Apps & features (Windows 10), sort by install date, and uninstall every program dated the day you followed the ad (Uninstall a program or app in Windows On uGetFix).
- 2
Run two Windows Security scans
Open Windows Security > Virus & threat protection and run a Full scan. Then choose Scan options > Microsoft Defender Offline scan > Scan now. Save your work first: the offline scan takes about 15 minutes and restarts the PC, and runs outside the normal Windows environment, so it can find malware that hides while Windows runs.
- 3
Reset the browser
Programs from ads often change the start page, the search engine or the extension list. Use the reset step for your browser below.
Adware may also have changed system files. A full scan and a reset normally deal with this; if Windows itself behaves oddly, repeat the offline scan before you reinstall. If you typed a password, card number or other details into a page an ad opened, change that password at once and tell your bank about the card.
How to keep it from happening again
Do
- On a free-software installer, choose Advanced or Custom, read each screen and untick every extra add-on, toolbar or plugin before you click Next. The Quick option accepts them for you.
- Get programs from the maker's own site or the Microsoft Store, not from a link in an ad or a download portal such as CNET or Softonic.
- Check updates only in the program itself or on the maker's official website. Flash Player is gone, so a "Flash update" is always fake.
- Block pop-ups, redirects and notifications: in Chrome, Settings > Privacy and security > Site settings > Notifications and Pop-ups and redirects. Do the same in your other browsers.
- Keep the free Microsoft Defender running with its definitions up to date; a full scan is under Windows Security > Virus & threat protection.
- Back up your documents with File History or OneDrive, so a bad install or a failing disk does not take them with it.
- A VPN on a public Wi-Fi hides your IP address from the sites you visit. It does not stop ads, scripts or malware.
Don't
- Download fake video, file or URL converters: they bring more trouble than the file is worth.
- Click a second download link on a download portal: it is often the installer of something else.
- Open an
.exeor.msithat a converter site handed you: a real conversion gives you a media file. - Click Allow on a notification prompt from a converter, streaming or adult-themed site.
Safer ways to get a file you want
A converter that asks for notifications or an install is the wrong tool. Use the platform's own option or software you chose on purpose.
| What you want | Safer way |
|---|---|
| Watch a YouTube video offline | Download below the video with YouTube Premium, on a signed-in account (YouTube Help) |
| Audio from a file you already own | Software from its maker's own site, installed on purpose and run on the file on your PC, not a website that asks you to allow notifications |
| Someone else's video | Ask the creator, or choose a video under a licence that allows reuse; most videos are protected by copyright and laws differ by country |
If you use an online converter anyway, use a browser profile with notifications blocked, skip every extension and "player", and scan any file that turned out to be a program instead of a media file.
Questions about Flv2mp3 ads
Is Flv2mp3 a virus?
Flv2mp3 is not a virus in the strict sense; our 2021 guide classed it as a potentially unwanted program and adware, a converter that showed ads and was listed on download portals.
In our check on 6 October 2026, flv2mp3.by showed a Russian-language blog with no converter, no ads, no redirect and no notification request, but that was one visit from Europe and a quiet visit does not clear a name.
We did not run the Windows program or any add-on, and we have no 2026 detection names. If you installed the program or allowed notifications in 2021, remove them and run a Windows Security scan.
Is flv2mp3.by safe?
On our one visit on 6 October 2026 flv2mp3.by showed nothing harmful, but we cannot call it safe. The address now serves a Russian-language blog called FLV Master, not the converter our 2021 guide described, and we could not find out who runs it or since when, because the .by registry has no public RDAP record.
The page contacted only Google Fonts, set no service worker and asked for no notifications. Adware often changes by country, device and time, so another visitor may see something else. If you open it, do not allow anything the page asks for.
What is Flv2mp3?
Flv2mp3 is a free converter that turned a YouTube link into MP3, MP4, MP4 HD, AVI or AVI HD files. Our 2021 guide described a web page at flv2mp3.by and a Windows program called FLV2MP3 listed on CNET's download site, version 1.0, added in April 2009.
The name comes from FLV, the Flash video format, and Adobe ended Flash Player support after 31 December 2020. Our 2021 guide called it adware because the page carried ads, some for chat and dating offers, and showed a notification prompt. In 2026 the address no longer shows a converter.
How do I remove Flv2mp3 from Windows?
Open Settings > Apps > Installed apps on Windows 11, or Apps & features on Windows 10, find FLV2MP3 or any converter you do not remember, and choose Uninstall. If it will not uninstall, press Ctrl + Shift + Esc, end its process and try again; also disable any converter in the Startup apps tab.
Then remove converter or downloader extensions from your browser, and delete flv2mp3.by from the browser's notification list if you ever allowed it. Finish with a full scan in Windows Security > Virus & threat protection if you ran any file that came from an ad.
Why did Flv2mp3 show ads for chat and dating sites?
The ads paid for the converter. Our 2021 picture shows three ad tiles under the conversion text, two of them for chat and dating offers, and our 2021 guide described adware ads as promoting apps, deals and chat with women.
Such ads are sold through ad networks, so the advertiser is not chosen by the site owner one by one, and adult-themed or deal ads are common on free converter and streaming pages. Clicking them can lead to scam or subscription pages, so close the tab. In our 2026 visit the site showed no ads at all.
Does Flv2mp3 collect my data?
The privacy policy in our 2021 picture says that when you use the service your IP address, country and other non-personal information about your device may be recorded:
- web requests
- browser type and language
- referring URL
- operating system and the date
- time of requests
It also lists search terms, uploaded content, correspondence and cookies. Our 2021 guide said the developers use this for targeted advertising; the part we pictured does not state that purpose.
We could not find that policy on flv2mp3.by in 2026, so we could not re-read it. Remove the program and clear cookies to limit it.
Why does the Flv2mp3 notification prompt matter?
A notification permission stays in your browser until you remove it. The 2021 converter page triggered a Chrome prompt that said the site wants to show notifications, with Block and Allow. If you clicked Allow, flv2mp3.by remains on the allowed list, and whoever controls the address can use it to push messages, which can be ads or fake alerts.
In Chrome open Settings > Privacy and security > Site settings > Notifications and remove the entry. In 2026 we saw no prompt on the page, but a permission you gave earlier is not affected by that.
Is it legal to convert YouTube videos to MP3?
It depends on the video and on your country. Most YouTube videos are protected by copyright, and copying someone else's work without permission can break the law whichever converter you use. YouTube's own way to keep a video for offline viewing is the Download button that YouTube Premium adds below the video on a signed-in account.
For anything else, ask the creator or choose material under a licence that allows reuse. Converting a file you own or made yourself is a different case, but it does not need a website that asks you to install software or allow notifications.
How do I convert FLV to MP3 without adware?
Convert only files you own, and do it on your own PC with software you downloaded from its maker's own site, not from a download-portal link or an ad.
Pick the Custom install and untick extras, then check Installed apps afterwards. Avoid websites that ask you to allow notifications, install a player or run an .exe before you get the file.
FLV is the old Flash video format and Flash Player was discontinued, so most videos are in other formats today. If a site offers a Flash update to play a file, it is false. Scan any download with Windows Security before you open it.
Will Fortect remove Flv2mp3?
Fortect scans Windows for malware and unwanted programs and repairs the system files and settings they change, and its free scan shows what it finds on your PC before you decide anything.
For Flv2mp3, follow the plan above as well: the browser steps take back permissions and settings that no scanner treats as a threat, and uninstalling the program that brought it removes the source.
Run Microsoft Defender's full scan and, if anything was found, its offline scan as a second opinion. If the symptoms are gone after the plan and both scans are clean, there is nothing more to do.
Sources
- flv2mp3.by home page (our test) (read October 6, 2026)
- Our 2021 guide to Flv2mp3 (pictures and text) (read October 6, 2026)
- Adobe: Flash Player End of Life general information (read October 6, 2026)
- Microsoft Learn: Run and review the results of a Microsoft Defender Offline scan (read October 6, 2026)
- Google Chrome Help: Use notifications to get alerts (no longer online) (read October 6, 2026)
- YouTube Help: Watch videos offline with YouTube Premium (no longer online) (read October 6, 2026)
- FTC: How to recognize, remove and avoid malware (read October 6, 2026)