Windows Support Alert: what it is and how to remove it
Windows Support Alert scam is a rogue technical support alert, which shows up on web browsers if an adware-type malware is installed on the system. Criminals use social engineering techniques to scare people into thinking that their devices are infected by a dangerous virus and offer to call +1-855-393-4537 number and connect with the "Microsoft tech support team."
Facts checked October 7, 2026. Removal steps tested on Windows 11 (26H2) and checked against Microsoft's and the browser makers' current documentation. Sections marked as our earlier report are the original text: they describe the threat as it was then and have not been reviewed since. The 2026 status, the removal steps and the questions are current.
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Windows Support Alert: summary
| Name | Windows Support Alert |
|---|---|
| Classification | Technical Support Scam |
| Symptoms | When browsing the web, a new tab window shows up and freezes the browser. The notification contains a mobile number and attempts to look like a legitimate Microsoft's notification. In addition, the web browser may display advertising content and redirect to suspicious websites |
| Related programs | This rogue pop-up emerges on the system due to adware infection, which creates a scheduled web browser's task to load a tech support scam window regularly. Therefore, any advertising malware can be the culprit of these pop-ups |
| Criminal contacts | +1-855-393-4537. Nevertheless, the provided telephone number may vary because the scam is regularly updated |
| Affected web browsers | Google Chrome, Mozilla Firefox, Internet Explorer, Microsoft Edge, Safari are primary targets. Nevertheless, it exhibits compatibility with other less popular web browsers as well |
| 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 10 more facts
| Danger | The pop-up itself is not dangerous. However, those who got tricked by the alert and called the given number may experience money loss or inadvertently allow criminals remotely connect to their devices |
|---|---|
| Detection names | No Microsoft detection name is known |
| Distribution | Not recorded in the old report |
| Damage | Not recorded in the old report |
| Type | Tech support scam page |
| Evidence | 4 write-ups by security sites; no sample analysed yet |
| Imitates | Microsoft support |
| Phone number | +1-855-393-4537 |
| First seen | 2 January 2021 |
| Facts checked | 7 October 2026 |
What the Windows Support Alert pop-up looks like
Windows Support Alert
Your system detected some unusual activity.
It might harm your computer data and track your financial activities
Please report this activity to +1-855-393-4537
Is the Windows Support Alert warning real?
- Phone number:
+1-855-393-4537
From our report of Jan 2021 · not reviewed since
More from our earlier report on Windows Support Alert
- Scam pop-ups on web browsers mean that the system is contaminated with malware.
- Thus, a full system scan with a reputable AV is required.
- Post-malware system may encounter errors, slowdowns, and similar malfunctions.
- In this case, optimize the system with utility.
- VIRUS ALERT FROM WINDOWS This computer is BLOCKED Do not close this window and restart your computer Your computer's registration key is Blocked.
- Why we blocked your computer?
- The window's registration key is illegal.
- This window is using pirated software.
- This window is sending virus over the Internet.
- This window is hacked or used from undefined location.
- We blocked this computer for your security.
- Contact windows helpline to reactivate computer.
What the Windows Support Alert scammers want
From our report of Jan 2021 · not reviewed since
Windows Support Alert pop-up is a scam that shows up on web browser due to adware infection
Windows Support Alert scam is a rogue technical support alert, which shows up on web browsers if an adware-type malware is installed on the system.
Criminals use social engineering techniques to scare people into thinking that their devices are infected by a dangerous virus and offer to call +1-855-393-4537 number and connect with the "Microsoft tech support team." However, we can assure you that this alert has nothing to do with Microsoft and that dealing with these people can be dangerous.
The first thing you need to know is that scammers, who are working behind this fake error message, rely on social engineering. Typically, Windows Support Alert appears on victims' desktop out of the sudden, while they are browsing the Internet. After being caught out of the sudden, they fall into frightening claims about detected malware.
The most important thing is to ignore the telephone number given in the alert because such scams seek to sign users up for paid and useless services. Besides, you can be tricked into downloading malware to your computer in the form of a useful tool that is supposed to fix a computer.
The fake warning message reads:
No matter how terrifying the message might sound, you must keep calm and never contact cyber criminals. Their only goal is to make easy money. Instead, you should remove adware from your computer using or any other software you might prefer.
From our report of Jan 2021 · not reviewed since
Reasons why crooks alert you about the supposed infection
The scam messages and fake pop-up ads are displayed for a reason.
First of all, they might ask for remote access to your machine and install malware. Beware that all these "powerful" optimizers and similar software that is promoted with the help of such scams do not work. In the worst-case scenario, hackers might try to install a keylogger or trojan to steal your personal information.
Following some "investigation" performed by fake technicians, you can also be asked for a payment in exchange for the bogus services provided. Alternatively, they might urge you to subscribe to fraudulent services that can lead you to the money loss every month.
Evidently, trusting cyber criminals is not a good idea. Their only goal is to steal your money, so you should waste no time and use our removal guide at the end of this post. However, continue reading if you are interested in how these scams get into your system.
Update 2020: one of the latest Windows Support alert scams displayed an aggressive Google Chrome window, which freezes the web browser and scares the victim with false claims that "This computer is BLOCKED." The message contains a supposedly Toll-Free Microsoft support telephone number 0800-051-7350. The alert says:
On the right side of the window, the user is asked to enter a valid Windows activation key, which should be provided by the Windows support team. However, criminals on the other side of the handset may try to get remote access to your PC or induce to install a trojan, keylogger, spyware on the system.
Therefore, if you see such and similar pop-up, close your web browser and remove the adware from the system. For that, use a professional anti-malware program and make sure to reset the web browser to prevent the pop-up from reappearing.
From our report of Jan 2021 · not reviewed since
To protect your system, be careful with free software
To prevent your system from displaying tech-support scams, make sure you take the needed steps to protect yourself from adware.
As adware mostly spreads with the help of bundling, experts recommend being careful when downloading free software from the web.
It might seem like a good idea to use Recommended settings while installing freeware, as it is advised by developers. However, it is a trick designed to conceal additional unwanted programs within the installation manager. Taking into account that users skip steps to rush the whole installation process, there is no surprise that they end up with adware or other unwanted programs installed on their computers.
Therefore, always use Advanced mode while installing freeware, as it is the only way to avoid installing additional components. If you are not sure whether you are affected by such PUP, look for suspicious signs in unexpected pop-ups: grammar mistakes within the text, amateur graphic design, etc.
How to get rid of the Windows Support Alert pop-up
The warning is a web page and your PC is not infected by it.
Close it, then remove what keeps bringing it back.
Step 1: Close the page without touching its buttons
Press Ctrl + Shift + Esc to open Task Manager, select the browser on Processes and click End task: buttons on the page, including Close and Cancel, can trigger downloads or more pop-ups. When you reopen the browser, do not restore the previous tabs.
Warning: Never call
+1-855-393-4537; Microsoft and antivirus companies do not put phone numbers in warnings.If the page opens again by itself, notifications or an extension are bringing it back, which the next steps fix. Task Manager works the same in Windows 11 and Windows 10.
Full procedure with screenshots: Close a frozen app (Task Manager, Force Quit) On uGetFix
Step 2: Scan the PC, then run the offline scan
A scan finds the parts of Windows Support Alert that the manual steps cannot see. In Windows Security > Virus & threat protection > Scan options, start a Full scan and quarantine what it reports.
Follow it with Microsoft Defender Antivirus (offline scan) > Scan now, which restarts the PC and checks the disk while Windows and the malware are not running.
It takes about 15 minutes and works the same in Windows 11 and Windows 10. If either scan finds something, run the full scan again after removal until it comes back clean.
Windows 11: Windows Security > Virus & threat protection > Scan options. Full procedure with screenshots: Run a Microsoft Defender Offline scan
Instructions for each browser and system
The detailed steps for every browser and system this guide covers. Open the one you use.
Uninstall from Windows
To get rid of the annoying pop-up from Windows, use the guide given below. Your task is to find all suspicious entries in Control Panel and uninstall them.
Uninstall from Windows 10/8:
- Type Control Panel into the Windows search box and open the result.
- Under Programs, select Uninstall a program.
Uninstall from Windows 7/XP:
- Click on Windows Start > Control Panel (Windows XP users should click on Add/Remove Programs).
- In Control Panel, select Programs > Uninstall a program.
Remove the unwanted program:
- In the Programs and Features window, look for any recently installed suspicious entries, select them, and click Uninstall.
- If User Account Control appears, click Yes to confirm, then complete the removal.
Remove from Google Chrome
Delete malicious extensions from Google Chrome:
- Open Google Chrome, click on the Menu (three vertical dots at the top-right corner) and select More tools > Extensions.
- In the newly opened window, you will see all the installed extensions. Uninstall all suspicious extensions related to the unwanted program by clicking Remove.
Clear cache and web data from Chrome:
- Click on Menu and pick Settings.
- Under Privacy and security, select Clear browsing data.
- Select Browsing history, Cookies and other site data, as well as Cached images and files.
- Click Clear data.
Change your homepage:
- Click menu and choose Settings.
- Look for a suspicious site in the On startup section.
- Click on Open a specific or set of pages and click on three dots to find the Remove option.
Reset Google Chrome:
If the previous methods did not help you, reset Google Chrome to eliminate all the unwanted components:
- Click on Menu and select Settings.
- In the Settings, scroll down and click Advanced.
- Scroll down and locate Reset and clean up section.
- Now click Restore settings to their original defaults.
- Confirm with Reset settings.
Remove from Microsoft Edge
Delete unwanted extensions from MS Edge:
- Select Menu (three horizontal dots at the top-right of the browser window) and pick Extensions.
- From the list, pick the extension and click on the Gear icon.
- Click Remove.
Clear cookies and other browser data:
- Click on the Menu (three horizontal dots at the top-right of the browser window) and select Settings > Privacy, search, and services..
- Under Clear browsing data, pick Choose what to clear.
- Select Cookies and other site data and Cached images and files. (apart from passwords, although you might want to include Media licenses as well, if applicable) and click on Clear.
Restore new tab and homepage settings:
- Click the menu icon and choose Settings.
- Then find On startup section.
- Click Remove next to any suspicious startup page.
Reset MS Edge if the above steps did not work:
- Press on Ctrl + Shift + Esc to open Task Manager.
- Click on More details arrow at the bottom of the window.
- Select Details tab.
- Now scroll down and locate every entry with Microsoft Edge name in it. Right-click on each of them and select End Task to stop MS Edge from running.
Delete extensions from MS Edge (Chromium):
- Open Edge and click select Settings > Extensions.
- Delete unwanted extensions by clicking Remove.
Clear cache and site data:
- Click on Menu and go to Settings.
- Select Privacy, search and services.
- Under Clear browsing data, pick Choose what to clear.
- Under Time range, pick All time.
- Select Clear now.
Reset Chromium-based MS Edge:
- Click on Menu and select Settings.
- On the left side, pick Reset settings.
- Select Restore settings to their default values.
- Confirm with Reset.
- This will disable extensions and reset startup pages but will not delete bookmarks, saved passwords, or browsing history.
Remove from Mozilla Firefox (FF)
Remove dangerous extensions:
- Open Mozilla Firefox browser and click on the Menu (three horizontal lines at the top-right of the window).
- Select Add-ons.
- In here, select the unwanted extension and click Remove.
Reset the homepage:
- Click three horizontal lines at the top right corner to open the menu.
- Choose Settings.
- Under Home, set your preferred homepage and new tab settings.
Clear cookies and site data:
- Click Menu and pick Settings.
- Go to Privacy & Security section.
- Scroll down to locate Cookies and Site Data.
- Click on Clear Data...
- Select Cookies and Site Data and Temporary cached files and pages, then click Clear.
Reset Mozilla Firefox
If clearing the browser as explained above did not help, reset Mozilla Firefox:
- Open Mozilla Firefox browser and click the Menu.
- Go to Help and then choose Troubleshooting Information.
- Under Give Firefox a tune up section, click on Refresh Firefox...
- Once the pop-up shows up, confirm the action by pressing on Refresh Firefox.
Delete from Safari
Remove dangerous extensions:
- Open Safari, click Safari in the menu at the top-left of the screen, and select Preferences.
- Go to the Extensions tab, look for any suspicious entries, and click Uninstall to remove them.
Clear history and website data:
- Click Safari in the menu and pick Clear History.
- Set Clear to all history and confirm with Clear History.
Reset Safari:
- Click Safari in the menu and select Preferences > Advanced.
- Enable Show Develop menu in menu bar.
- From the menu bar, click Develop and select Empty Caches.
Delete from macOS
Remove the unwanted application:
- From the menu bar, select Go > Applications.
- In the Applications folder, look for any suspicious entries, then drag them to Trash (or right-click and pick Move to Trash).
Delete leftover files and folders:
- Select Go > Go to Folder.
- Enter /Library/Application Support and remove any suspicious folders related to the unwanted program.
- Repeat the same check in the /Library/LaunchAgents and /Library/LaunchDaemons folders, deleting any suspicious entries.
- Finally, empty the Trash to permanently remove the leftovers.
Stream videos without limitations, no matter where you are
There are multiple parties that could find out almost anything about you by checking your online activity.
While this is highly unlikely, advertisers and tech companies are constantly tracking you online. The first step to privacy should be a secure browser that focuses on tracker reduction to a minimum.
Even if you employ a secure browser, you will not be able to access websites that are restricted due to local government laws or other reasons. In other words, you may not be able to stream Disney+ or US-based Netflix in some countries. To bypass these restrictions, you can employ a powerful VPN, which provides dedicated servers for torrenting and streaming, not slowing you down in the process.
Data backups are important - recover your lost files
Ransomware is one of the biggest threats to personal data.
Once it is executed on a machine, it launches a sophisticated encryption algorithm that locks all your files, although it does not destroy them. The most common misconception is that anti-malware software can return files to their previous states. This is not true, however, and data remains locked after the malicious payload is deleted.
While regular data backups are the only secure method to recover your files after a ransomware attack, tools such as can also be effective and restore at least some of your lost data.
From our report of Jan 2021 · not reviewed since
Remove Windows Support Alert virus from your computer
The most reliable way to remove Windows Support Alert scam is to use a genuine anti-malware tool.
You have plenty to choose from the list given below. However, beware that your security software must be up-to-date before a scan to make sure that all suspicious components are gone from your computer. Otherwise, BHOs (browser helper objects) can reinstall malware right after rebooting the system.
However, if you possess decent computer skills and do not want to employ additional software, you can attempt to uninstall adware yourself. Just follow our guide below carefully, and you will be able to enjoy a problem-free browser again.
Once a full PUP removal is performed, you should take extra precautions:
- Reset passwords on all your accounts;
- Contact your bank to revert payments if any was performed by you or other people;
- Apply security software updates as soon as they are available.
Questions about Windows Support Alert
Should I trust a page that says "Your system detected some unusual activity."?
No. Genuine security software reports problems in its own window or in the Windows notification area, never on a website you were redirected to. Pages that say "Your system detected some unusual activity." are built to frighten you into calling a support number, buying a licence through a referral link or installing a so-called cleaner.
Do none of those. Close the tab and, if it opens again by itself, remove the sites allowed to send notifications and any extension you do not recognise. If you already called, paid or installed something, follow the matching section of this guide: each case needs a different next step, from calling your bank to removing a remote-access tool.
Is +1-855-393-4537 a real Microsoft support number?
No. Microsoft does not put phone numbers in warnings, pop-ups or error messages, and its support never calls you first about a virus. The number +1-855-393-4537 is used by a scam call centre that pays for traffic to fake warning pages.
If you need help from Microsoft, go to support.microsoft.com yourself and start from there. Never use a number that appeared in a pop-up, an unexpected e-mail or a search ad that looks like a support listing. If you already called, follow the steps in this guide for callers:
- remove any remote tool
- change passwords from another device
- contact the bank if you paid
The "Your system detected some unusual activity." page made me install something. What now?
Uninstall it first. Open Settings > Apps > Installed apps, sort the list by install date and remove whatever appeared when the page showing "Your system detected some unusual activity." told you to install it. Check the browser's extensions as well, since some pages push an extension instead of a program.
Then run a full scan with Microsoft Defender, and an offline scan if anything is found. If the program was a remote-access tool, or if you typed passwords while it was installed, change those passwords from another device and turn on two-step verification. Keep the file name and the page address; they are useful if you report the scam.
I paid the people at +1-855-393-4537. Can I get my money back?
Often yes, if you act quickly. Card payments can be disputed through your bank as fraud; call the number on the back of the card and explain that you paid a tech support scammer reached at +1-855-393-4537. Bank transfers are harder, but the bank may recall the payment if you call the same day.
Gift cards can sometimes be frozen if you contact the card issuer with the codes before they are spent. PayPal and similar services have their own dispute forms. Keep every receipt and message, and report the scam to the police or the national fraud office, since banks often ask for a report number.
Does Microsoft support know about Windows Support Alert?
Large brands such as Microsoft support are aware that scammers copy their names and logos, and most have pages where you can report such abuse. They do not run these pages and do not profit from the warnings themselves.
Sometimes an affiliate of an antivirus vendor sends traffic through fake alerts, which breaks the vendor's rules and gets the affiliate banned when reported. If you want to help, report the page address to the brand's security team and to your browser through its report option.
Is +1-855-393-4537 a real support number?
No. +1-855-393-4537 appears on Windows Support Alert and is answered by a scam call centre. Microsoft and antivirus companies do not put phone numbers in security warnings, and they never ask you to call because of a web page.
If you need real support from Microsoft support, find the contact page on its official site by typing the address yourself. Scammers sometimes buy search ads for support numbers too, so check that the site you find is the real one. If the number reached you by phone instead, hang up.
I closed it, but it appeared again the next day. Why?
A page that returns on its own has a trigger. Look at how it appeared: from a pop-up in the corner of the screen means a notification permission; on start-up means a session restore or a changed start page; while browsing any site means an extension; on one particular site means that site's ads.
Each has a quick fix in the browser settings. If none of them explains it, reset the browser, which clears permissions, extensions and start pages together.
Which browser settings protect against fake alerts?
Three matter most. First, notifications: set your browser to ask before allowing them, and block sites you do not trust. Second, reputation checks: SmartScreen in Edge and Safe Browsing in Chrome warn you before known scam pages load, and Firefox has its own deceptive-content protection under Privacy & Security.
Third, pop-ups and redirects: keep the default blocking on. Add a reputable ad blocker if fake alerts keep reaching you through ads on sites you use. Review the notification list every few months.
How did Windows Support Alert find me?
It did not target you personally. Pages like this buy traffic from shady ad networks and from hacked sites, and they show A browser warning that reads "Your system detected some unusual activity." to whoever is redirected to them.
Mistyped addresses, streaming and download sites, and earlier clicks on Allow for notifications are the most common entry points. Nothing about your PC was scanned or known in advance. Once you remove the trigger in the browser, the page has no way to reach you again unless you meet a similar ad.
Will Fortect remove Windows Support Alert?
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 Windows Support Alert, 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
- Symantec: Web Attack: Fake Tech Support Website (read October 7, 2026)
- Wikipedia, the free encyclopedia: Social engineering (security) (read October 7, 2026)
- losvirus: Losvirus. Security guides in Spanish (read October 7, 2026)
- FTC: How to spot, avoid and report tech support scams (read October 7, 2026)
- FTC: How to recognize, remove and avoid malware (read October 7, 2026)