Trojan.Win32.Dialer.a: what it is and how to remove it
Trojan.Win32.Dialer.a is a type of virus that uses a telephone line to connect users' computers to premium-rated services. As a result, victims might lose money, click on malicious links, infected their machines with more malware, or disclose their personal information to cybercriminals.
Facts checked October 6, 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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Trojan.Win32.Dialer.a: summary
| Distribution | Spam email attachments or hyperlinks. Also, could be automatically installed by an already existing Trojan |
|---|---|
| Damage | Installation of other malicious software, financial losses due to premium-rate numbers being dialed |
| Name | Trojan.Win32.Dialer.a |
| Type | Malware, dialer |
| Detection names | No Microsoft detection name is known |
| Symptoms | An unknown program in Installed apps |
| 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 3 more facts
| Evidence | One write-up by a security site; details still limited |
|---|---|
| First seen | 26 April 2021 |
| Facts checked | 6 October 2026 |
What Trojan.Win32.Dialer.a does on an infected PC
From our report of Apr 2021 · not reviewed since
Trojan.Win32.Dialer.a - malware that hijacks your internet traffic
Trojan.Win32.Dialer.a is a type of virus that uses a telephone line to connect users' computers to premium-rated services.
As a result, victims might lose money, click on malicious links, infected their machines with more malware, or disclose their personal information to cybercriminals.
It is also common that these types of Trojans often automatically redirect users' web traffic to pornographic websites. Hence, those infected might find the content inappropriate, or it could be exposed to children. If you have been suffering from strange redirects to adult sites and other strange behavior, you need to remove this virus from your system ASAP.
Just like any other malicious software, dialer malware uses illicit methods for its distribution. In most cases, victims might get infected due to another Trojan already present on the device. Alternatively, users might also be tricked into downloading it from malicious websites, believing it is a useful program or opening spam emails that include macro-infused attachments.
Malicious dialers operate on a relatively simple way - it changes the settings of the dial-up without permission. This allows the malware to perform all its malicious activities, i.e., connect to a website that uses premium-rate costs. This harmful activity brings benefits to cybercriminals operating those destination websites.
While the financial losses if one of the negative sides of the infection, the problem is also evident when it comes to inappropriate content.
To make matters worse, there could another Trojan already installed on your computer if Trojan.Win32.Dialer.a is present. During its operation, it might perform the following tasks:
Also, to clean up your web browsers and fixing potential damage caused by the virus to Windows system files, use .
- Download install other malicious programs
- Update itself with new features
- Log keystrokes and record mouse inputs
- Open a backdoor on the system, allowing a full remote control to the attackers
- Gather personal information, such as credit card details, login data, etc.
From our report of Apr 2021 · not reviewed since
Use precautionary measures to avoid malware
As evident, no users would install malicious programs on their computers intentionally.
Despite this, most infections happen precisely when victims install malware themselves, although they are tricked into doing so in most cases. Trojans, essentially, are not defined by their operation but rather the distribution method.
Users who install Trojans on their systems believe that the executable they launched is perfectly safe due to one reason or another. In fact, any executable can be called anything to deceive potential victims. It does not matter where such files come from - malicious spam emails, software cracks, pirated program installers, fake anti-spyware apps, or fake notifications on various websites.
In order to protect yourself from such malware attacks, equip your system with security software that would warn you about potential danger. It means that an antivirus and web shield are both needed. Also, avoiding high-risk websites and not opening suspicious emails can decrease the risk of infection significantly.
From our report of Apr 2021 · not reviewed since
More from our earlier report on Trojan.Win32.Dialer.a
- The easiest way to delete malware is by performing a full scan with antivirus software
- Employ to fix Windows system file damage done by malware automatically
How to remove Trojan.Win32.Dialer.a
A loader's job is to install other malware, so treat the PC as infected with more than one program until the scans are clean.
Step 1: Delete scheduled tasks that bring it back
Open Task Scheduler from the Start menu and click Task Scheduler Library. Select each task you do not recognise and read the Actions tab:
- a task that starts a file in
%AppData%or%Temp% - runs
powershellwith a long encoded line - opens a web address belongs to Trojan.Win32.Dialer.a or a similar program
Right-click such a task and choose Delete, and check the subfolders too. Leave tasks from Microsoft, your PC's maker and programs you use. Task Scheduler is the same in Windows 11 and Windows 10.
Windows 11: Task Scheduler Library, the task selected, the Actions tab shows the file it runs. Full procedure with screenshots: Remove what malware leaves behind in Windows
- a task that starts a file in
Step 2: Remove it from startup
Whatever Trojan.Win32.Dialer.a installed usually starts with Windows. Open Task Manager with Ctrl + Shift + Esc, go to Startup apps in Windows 11 or the Startup tab in Windows 10, and disable what you do not know, starting with entries that have an empty Publisher column.
Open file location on the right-click menu shows the file, which helps you decide and tells you what to delete later. Disabling is safe: if something you need stops working, switch it back on.
Full procedure with screenshots: Stop apps from opening at startup On uGetFix
Step 3: Delete the folders left behind
What the uninstaller leaves behind is usually in the user folders. Open File Explorer, switch on View > Show > Hidden items (in Windows 10 View > Hidden items), and go through
%LocalAppData%,%AppData%, %ProgramData% and the two Program Files folders.Sort by Date modified and delete folders that appeared together with the problem and belong to no program you use. Folders with random names that hold
.exe,.dll, .js or .ps1 files are the strongest sign.Full procedure with screenshots: Remove what malware leaves behind in Windows
Step 4: Scan the PC, then run the offline scan
Open Windows Security > Virus & threat protection > Scan options, run a Full scan and remove everything it finds. Then select Microsoft Defender Antivirus (offline scan) and click Scan now: the PC restarts and scans before Windows loads, which finds files that hide while Windows runs.
Save your work first, because the offline scan takes about 15 minutes. Both scans are built into Windows 11 and Windows 10, and a second scanner from another vendor is a useful extra opinion.
Windows 11: Windows Security > Virus & threat protection > Scan options. Full procedure with screenshots: Run a Microsoft Defender Offline scan
Step 5: Change passwords from another device and sign out other sessions
Assume that the passwords saved in this PC's browsers, and the accounts that were open in them, are known to the attacker. From a phone or a clean computer, change the e-mail password first, then banking, shopping, social and gaming accounts.
Use each service's option to sign out of all other sessions, because stolen cookies keep a session open even after a password change. Turn on two-step verification on each account. Wait with the infected Windows 11 or Windows 10 PC until the scans are clean.
Full procedure with screenshots: Turn on two-step verification / secure a hacked account
Instructions for each browser and system
The detailed steps for every browser and system this guide covers. Open the one you use.
Manual removal using Safe Mode
Important! →
Manual removal guide might be too complicated for regular computer users. It requires advanced IT knowledge to be performed correctly (if vital system files are removed or damaged, it might result in full Windows compromise), and it also might take hours to complete. Therefore, we highly advise using the automatic method provided above instead.
Step 1. Access Safe Mode with Networking
Manual malware removal should be best performed in the Safe Mode environment.
Windows 7 / Vista / XP
- Click Start > Shutdown > Restart > OK.
- When your computer becomes active, start pressing F8 button (if that does not work, try F2, F12, Del, etc. - it all depends on your motherboard model) multiple times until you see the Advanced Boot Options window.
- Select Safe Mode with Networking from the list.
Windows 10 / Windows 8
- Right-click on Start button and select Settings.
- Scroll down to pick Update & Security.
- On the left side of the window, pick Recovery.
- Now scroll down to find Advanced Startup section.
- Click Restart now.
- Select Troubleshoot.
- Go to Advanced options.
- Select Startup Settings.
- Press Restart.
- Now press 5 or click 5) Enable Safe Mode with Networking.
Step 2. Shut down suspicious processes
Windows Task Manager is a useful tool that shows all the processes running in the background. If malware is running a process, you need to shut it down:
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Click on More details.
- Scroll down to Background processes section, and look for anything suspicious.
- Right-click and select Open file location.
- Go back to the process, right-click and pick End Task.
- Delete the contents of the malicious folder.
Step 3. Check program Startup
- Press Ctrl + Shift + Esc on your keyboard to open Windows Task Manager.
- Go to Startup tab.
- Right-click on the suspicious program and pick Disable.
Step 4. Delete virus files
Malware-related files can be found in various places within your computer. Here are instructions that could help you find them:
- Type in Disk Cleanup in Windows search and press Enter.
- Select the drive you want to clean (C: is your main drive by default and is likely to be the one that has malicious files in).
- Scroll through the Files to delete list and select the following:
Temporary Internet Files
Downloads
Recycle Bin
Temporary files - Pick Clean up system files.
- You can also look for other malicious files hidden in the following folders (type these entries in Windows Search and press Enter):
%AppData%
%LocalAppData%
%ProgramData%
%WinDir%
After you are finished, reboot the PC in normal mode.
From our report of Apr 2021 · not reviewed since
Make Trojan.Win32.Dialer.a removal an easy task
While it is possible to eliminate malware manually, it is highly not recommended for regulars computer users.
Malicious programs perform a variety of changes to the infected devices and drop thousands of malicious files. Hence, if some of the components are not deleted correctly, the re-infection might occur. What makes it worse is that users would believe they are safe while the virus would still be operating in the background.
Therefore, you should download, install, and perform a full system scan with or another reputable anti-malware software to remove Trojan.Win32.Dialer.a automatically. If this malware is interfering with this process in any way, access Safe Mode as explained below and perform elimination from there. After that, use to fix virus damage quickly and efficiently.
After removal: passwords, accounts and prevention
Your passwords after Trojan.Win32.Dialer.a
Removing Trojan.Win32.Dialer.a does not undo what it may already have sent out while the PC showed trojan.Win32.Dialer.a in the list of installed apps.
Treat saved browser passwords and logged-in sessions on this PC as known to the attacker.
From another device, change the e-mail password first and end all its sessions. Then do the same for the bank, PayPal, Microsoft, Google and Apple accounts. Stolen session cookies keep working after a password change until you sign out everywhere.
Move crypto to a new wallet created on a clean device. A step-by-step order for every kind of account is in our guide to account security after an infection.
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.
Questions about Trojan.Win32.Dialer.a
Can I safely uninstall Trojan.Win32.Dialer.a?
If you did not install Trojan.Win32.Dialer.a yourself and it is not part of your hardware or a program you rely on, yes. Uninstalling an unwanted program does not harm Windows. Before you do, search the exact name and publisher to be sure it is not a driver tool, a printer utility or a game launcher with an odd name.
Then remove it from Settings, Apps, Installed apps. Ignore any offers or warnings in its uninstaller about losing protection or performance. Afterwards check Startup apps and your browsers for leftovers, and restart once to confirm that it does not reinstall itself.
How do I stop programs like Trojan.Win32.Dialer.a from being installed again?
Most unwanted programs arrive through installers, so the fix is in how you install software. Download programs from their official sites or the Microsoft Store, not from download portals or ads above search results. During setup, choose Custom or Advanced installation and untick every extra offer, including browsers, toolbars and optimizers.
Decline update prompts that appear inside other programs unless you know them. In Windows Security, turn on reputation-based protection and potentially unwanted app blocking. These steps would most likely have stopped Trojan.Win32.Dialer.a before it reached the app list.
Which malware family is Trojan.Win32.Dialer.a?
That is not known yet. Trojan.Win32.Dialer.a has been reported by people who saw trojan.Win32.Dialer.a in the list of installed apps, but no sample has been analysed publicly, so security companies have not assigned it to a family. The name you see may be a file or program name chosen by the authors, not a family name.
This does not stop you from removing it: the startup points, the offline scan and the account steps are the same for most families of this type. If Microsoft Defender or another scanner gives the file a detection name, write it down; that name is the best clue to the family and is useful when you report the incident.
Is it safe to do online banking after seeing trojan.Win32.Dialer.a in the list of installed apps?
Not on that PC until it is clean. A program that produces trojan.Win32.Dialer.a in the list of installed apps runs with your rights and could read what you type or what the browser shows. Use a phone or another computer for banking and for changing passwords.
When the offline scan of the affected PC is clean and nothing suspicious starts with Windows any more, you can go back to using it. Check your bank statements for the past weeks either way, and call the bank if anything looks unfamiliar; banks can block cards and reset access quickly.
Is a trojan infection worth reporting to the police?
If there was harm, yes. Unauthorised payments, accounts used for fraud, blackmail or a remote session during a scam call all belong in a report, and banks often ask for its reference number before they refund anything.
If antivirus caught Trojan.Win32.Dialer.a before it ran and nothing was misused, there is nothing to report. Keep the evidence anyway:
- protection history
- the original download
- the dates
Businesses may also have to notify a data protection authority if personal data could have been accessed.
Should I reset my PC because of Trojan.Win32.Dialer.a?
Only if the signs point to deeper access. Reset when you see trojan.Win32.Dialer.a in the list of installed apps again after removal, when Windows Security cannot start or update, when remote access tools you did not install keep appearing, or when you simply cannot trust the PC any more.
Otherwise, the plan in this guide plus an offline scan is enough. If you do reset, choose Remove everything and Cloud download for a fresh copy of Windows, restore only documents and photos, and reinstall programs from their official sites. Change important passwords from the clean system afterwards.
Why didn't my antivirus stop Trojan.Win32.Dialer.a?
New trojan builds are packed and changed often so that signatures do not match, and some are signed with stolen or bought certificates. Many arrive inside password-protected archives, which scanners cannot open until you extract them.
Some downloads also tell the user to turn off the antivirus "because it gives false alarms", a common line in cracked software instructions. Keep real-time protection on, never disable it for an installer, and run the offline scan whenever you suspect something slipped through.
What are the signs of a trojan infection?
Most trojans try to leave no visible signs, so look for side effects. Common ones:
- Windows Security turned off or unable to update
- new entries in Startup apps or Task Scheduler
- programs in Installed apps you did not install
- browser settings that changed by themselves
- unusual network activity while the PC is idle
- password-reset or login-alert e-mails you did not trigger
None of these proves an infection on its own. Together with an antivirus alert naming Trojan.Win32.Dialer.a, they are a strong reason to follow the full plan.
Can Trojan.Win32.Dialer.a spread to other devices on my network?
Most trojans aimed at home users stay on the PC they infected, but an attacker with remote access can look at the network, open shared folders and try passwords on other devices. Loaders sometimes deliver worms or ransomware that do spread.
Disconnect the PC while cleaning, run a full scan on other Windows PCs, change the router's admin password and the Wi-Fi password if they were saved on the infected PC, and update the router's firmware. If other PCs show the same detection, treat them as infected too.
Will Fortect remove Trojan.Win32.Dialer.a?
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 Trojan.Win32.Dialer.a, 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
- FTC: How to recognize, remove and avoid malware (read October 6, 2026)
- Microsoft Learn: Microsoft Defender Offline (read October 6, 2026)
- Microsoft Learn: How Microsoft names malware (read October 6, 2026)