Trojan.Agent.Trace: what it is and how to remove it
Trojan.Agent.Trace is a computer trojan, which means it is one of the most dangerous PC infections you should be aware of. Trojans are malicious programs that stay silent and do not reveal their existence since their purpose is to be undetected.
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.
Automatic
Get a free scan and check if your PC is infected.
Fortect finds malware, unwanted programs and the Windows damage they leave behind, and repairs it in one pass.
An automatic scan can look at Snsapi.dll and the other programs installed around the same time.
Do it yourself · free Remove Trojan.Agent.Trace yourself 6 steps, about 18 minutes, no software needed.
Start the steps
Trojan.Agent.Trace: summary
| Distribution | Malicious spam emails, software cracks/keygens/loaders, pirated programs, fake updates, etc. |
|---|---|
| Name | Trojan.Agent.Trace |
| Type | Trojan |
| Dangers | Trojans can perform a variety of different functions on the system, including information theft and system damage |
| Malware removal | Perform a full system scan with powerful security software like anti-malware |
| Detection names | No Microsoft detection name is known |
| 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 6 more facts
| Damage | Not recorded in the old report |
|---|---|
| Symptoms | An unknown process in Task Manager |
| Evidence | One write-up by a security site; details still limited |
| File names | Snsapi.dll |
| First seen | 9 March 2021 |
| Facts checked | 6 October 2026 |
What Trojan.Agent.Trace does on an infected PC
From our report of Mar 2021 · not reviewed since
Promotional ads allow malicious programs to enter the computer system
Trojans can be silently downloaded into your system without your knowledge.
It depends on what websites do you like to visit and what content do you click on while browsing the web. Usually, trojans are waiting for inattentive users in shady Internet sites such as pornographic content sites, gambling websites, and so on.
Be aware of the fact that you can install a trojan along with fake software updates, so if you ever see a pop-up message while browsing the web that urges you to update Java or Flash Player, close such message and quit the website you are browsing.
The chances are, you have come across a malicious or deceptive website. What is more, you can install Trojan.Agent.Trace virus by downloading suspicious email attachments sent by unknown senders and also by downloading infectious free applications.
It is hard to identify malicious files and programs since the world wide web provides various entertaining content, so the best way to stop malware from entering your computer system is to use anti-malware software.
What Trojan.Agent.Trace can steal or download
From our report of Mar 2021 · not reviewed since
Trojan.Agent.Trace is a computer trojan, which means it is one of the most dangerous PC infections you should be aware of.
Trojans are malicious programs that stay silent and do not reveal their existence since their purpose is to be undetected. However, this type of malware wreaks havoc on the computer system.
Trojan.Agent.Trace malware corrupts Windows Registry, deletes important system files, also causes Internet connection problems and other inconveniences. You might also notice that you cannot open some computer programs anymore - it is because Agent.Trace trojan obstructs you from opening them. Normally, you will receive a pop-up error message that will inform you about Snsapi.dll or other relevant file's absence.
There are more reasons why you should remove Trojan.Agent.Trace as soon as you notice its presence. This Trojan horse uses your Internet connection despite the fact that it blocks access to it for you.
It communicates with its remote server and organizes malicious activities. If your computer was compromised, Trojan.Agent.Trace malware will have full control and access to it, and unfortunately, it is going to use this power for bad intentions.
Trojans are infamous for their ability to download and execute other malicious infections, such as ransomware, worms, and other computer viruses.
In fact, it can bring any kind of spyware or malware to your computer, spy on you, collect personally identifiable information (such as your credit card information, passwords, full name, and similar sensitive data) and use this information to rob your bank account or use your information for sinister purposes.
The bad news is that Trojan.Agent.Trace is hard to detect since its only unfolding feature is that it makes the compromised computer run extremely slow. Make sure to repair any damage with or a similar app.
You can also perform a full Trojan.Agent.Trace removal with it just in a few clicks. Double-check before you move on with any other procedures on the device.
How to check the PC for Trojan.Agent.Trace
- File:
Snsapi.dll
How to remove Trojan.Agent.Trace
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: Check where Snsapi.dll runs from and stop it
Snsapi.dllis the part you can see, and its location tells you whether it belongs there. Right-click it on the Processes page of Task Manager and choose Open file location, then right-click the file > Properties > Digital Signatures to see who signed it.An unsigned file, or one in a user folder such as
%AppData%, is the one to remove: end the task, then delete the file.Note the folder name, because the same folder usually holds its other files. This is the same in Windows 11 and Windows 10.
Full procedure with screenshots: Close a frozen app (Task Manager, Force Quit) On uGetFix
Step 2: 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.Agent.Trace 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 3: Remove it from startup
Whatever Trojan.Agent.Trace 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 4: 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 5: 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 6: 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.
Scan your system with anti-malware
If you are a victim of ransomware, you should employ anti-malware software for its removal. Some ransomware can self-destruct after the file encryption process is finished. Even in such cases, malware might leave various data-stealing modules or could operate in conjunction with other malicious programs on your device.
or can detect and eliminate all ransomware-related files, additional modules, along with other viruses that could be hiding on your system. The security software is really easy to use and does not require any prior IT knowledge to succeed in the malware removal process.
From our report of Mar 2021 · not reviewed since
A proper method to remove Trojan.Agent.Trace virus
If you have detected Trojan.Agent.Trace virus on your computer, get rid of it as soon as you can.
As we have already mentioned, it tracks your personally-identifiable information, corrupts system files, and can fetch in additional malicious programs to your computer.
Trojan.Agent.Trace removal process might be difficult since this threat is extremely hard to detect and remove manually. You can try or for the job.
You should remove Trojan.Agent.Trace using a tool like anti-malware, so the process should be finished automatically since proper computer security programs are programmed to detect and destroy all malicious components of such computer viruses. In addition, you should be concerned about the file damage, so run to fix any.
After removal: passwords, accounts and prevention
Accounts come next
Because the PC showed an unfamiliar process called Snsapi.dll in Task Manager, a sign of a program that could read browser data, the clean-up is only half of the work.
The other half happens in your online accounts.
Change passwords from a clean device, beginning with e-mail; sign out of all sessions; check forwarding rules and recovery phone numbers; and turn on two-step verification with an authenticator app or a passkey. Ask your bank to replace cards saved in the browser.
Why the order matters and what to check in each account: secure your accounts after malware.
Protect your privacy - employ a VPN
There are several ways how to make your online time more private - you can access an incognito tab.
However, there is no secret that even in this mode, you are tracked for advertising purposes. There is a way to add an extra layer of protection and create a completely anonymous web browsing practice with the help of VPN. This software reroutes traffic through different servers, thus leaving your IP address and geolocation in disguise.
Besides, it is based on a strict no-log policy, meaning that no data will be recorded, leaked, and available for both first and third parties. The combination of a secure web browser and VPN will let you browse the Internet without a feeling of being spied or targeted by criminals.
No backups? No problem. Use a data recovery tool
If you wonder how data loss can occur, you should not look any further for answers - human errors, malware attacks, hardware failures, power cuts, natural disasters, or even simple negligence.
In some cases, lost files are extremely important, and many straight out panic when such an unfortunate course of events happen. Due to this, you should always ensure that you prepare proper data backups on a regular basis.
If you were caught by surprise and did not have any backups to restore your files from, not everything is lost. is one of the leading file recovery solutions you can find on the market - it is likely to restore even lost emails or data located on an external device.
Questions about Trojan.Agent.Trace
What is Snsapi.dll and why is it running?
Every process is started by something:
- a program you installed
- a Windows service
- a scheduled task
- a startup entry
To learn why Snsapi.dll runs, find its file with Open file location in Task Manager, then look for an entry pointing to that file in Settings > Apps > Startup and in Task Scheduler.
Sort Installed apps by date to see what arrived when the process first appeared. Once you know the owner, you can decide whether to keep it, switch it off at startup or uninstall it completely.
Can I delete the Snsapi.dll file?
Only after you know what it belongs to. If Snsapi.dll is part of a program, uninstall that program through Settings instead, so its services and tasks go too. If it belongs to nothing and is unsigned, end the process, disable whatever starts it and then delete its folder.
Do not delete files from the Windows folder or files signed by Microsoft: those are part of the system, and removing them can stop Windows from starting. When in doubt, run a Microsoft Defender scan first and let it decide.
Can I just delete Snsapi.dll?
Deleting Snsapi.dll by hand rarely removes Trojan.Agent.Trace. While the trojan runs, Windows may refuse to delete the file, and if you succeed, a scheduled task, a service or a second copy may bring it back at the next restart.
The file can also be only one part of the infection: loaders and remote access tools often install other programs. Use the Microsoft Defender offline scan, which removes the file together with its startup entries before Windows loads, and then check startup items and scheduled tasks as described in the plan.
Can Trojan.Agent.Trace 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.
Can I keep using the PC while Trojan.Agent.Trace is on it?
Not for anything that matters. As long as the program behind an unfamiliar process called Snsapi.dll in Task Manager runs, it can see what you type and what the browser stores, and it may download more malware. Disconnect the PC from the internet while you remove it, and do your banking, e-mail and password changes from another device.
Once the offline scan finds nothing and the sign does not return after a few restarts, normal use is fine. If the scan keeps finding new items, or you cannot remove the startup entry, a reset of Windows is the safer choice.
Which malware family is Trojan.Agent.Trace?
That is not known yet. Trojan.Agent.Trace has been reported by people who saw an unfamiliar process called Snsapi.dll in Task Manager, 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.
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.Agent.Trace, they are a strong reason to follow the full plan.
Should I reset my PC because of Trojan.Agent.Trace?
Only if the signs point to deeper access. Reset when you see an unfamiliar process called Snsapi.dll in Task Manager 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.
Can a normal remote support program be a backdoor?
Yes. Tools such as AnyDesk, TeamViewer and ScreenConnect are legitimate, but whoever controls the account behind them controls the PC. Scammers install them during fake support calls, and some trojan campaigns install them silently because antivirus programs do not flag a genuine, signed product.
If you find one you did not set up, uninstall it, check Startup apps for related entries and change passwords from another device. If money or accounts were involved, call your bank and report the incident.
Will Fortect remove Trojan.Agent.Trace?
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.Agent.Trace, 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)