Worm Bagle.f: what it is and how to remove it
Worm Bagle.f is the infection that spreads on Windows devices and can act as a vector for other threat infections. Worms, in most cases, act as a primary method to infect the system, so the additional threat can be installed without users' knowledge.
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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Worm Bagle.f: summary
| Distribution | Malicious code gets distributed via file attachments added to emails |
|---|---|
| Name | Worm Bagle.f |
| Type | Worm, malware |
| Detection names | No Microsoft detection name is known |
| Damage | Not recorded in the old report |
| 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 Worm Bagle.f does
From our report of Apr 2021 · not reviewed since
Worm Bagle.f is the type of a known worm that is a mass-mailing threat
Worm Bagle.f is the infection that spreads on Windows devices and can act as a vector for other threat infections.
Worms, in most cases, act as a primary method to infect the system, so the additional threat can be installed without users' knowledge. The malicious file itself might not act as dangerous and delete its data once the ransomware or a trojan is injected. There are many versions of this worm and it is known for a long time now.
Worm Bagle.f is an Internet worm and spreads by e-mail and popular file-sharing programs. In e-mail, it usually comes in a password-protected archive file or via MS document. It terminates some antivirus processes and has an integrated trojan, which can be used by attackers to get full control over your system.
It is recommended to enter the Safe Mode with Networking before doing anything, so the anti-malware tool can find and remove parasites and other pieces related to the infection. Tools like or can be used to clear infections then.
From our report of Apr 2021 · not reviewed since
More from our earlier report on Worm Bagle.f
- You can remove the infection with anti-malware tools and a proper system scan
- The machine can get significantly affected by the threat, so you should run and repair the affected parts
How to remove Worm Bagle.f
Clean the USB drives as well as the PC, or the worm comes back the next time a stick is plugged in.
Step 1: Clean the USB drives
Worm Bagle.f spreads through USB sticks, so every drive used in this PC is suspect.
In File Explorer, switch on hidden items, delete the shortcuts that look like your folders, and run
attrib -h -r -s /s /d E:\*.*in Command Prompt (with your drive's letter) to restore the hidden ones.Right-click the drive and choose Scan with Microsoft Defender. Turn off AutoPlay for removable drives in Settings > Bluetooth & devices > AutoPlay (Windows 11) or Devices > AutoPlay (Windows 10).
Full procedure with screenshots: Run a Microsoft Defender Offline scan
Step 2: Remove it from startup
Whatever Worm Bagle.f 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 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 Worm Bagle.f 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 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
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.
After removal and prevention
Protect the files you restore
Restore only after the scans are clean and the PC no longer shows worm Bagle.f in the list of installed apps; otherwise the restored copies can be damaged again.
Then build a backup that survives the next infection:
- one copy in the cloud with version history
- one on an external drive that is disconnected between backups
- the working copy on the PC
Version history matters because a backup that syncs damaged files overwrites the good ones.
How to do this with the tools built into Windows: the 3-2-1 backup rule on Windows.
Access your website securely from any location
When you work on the domain, site, blog, or different project that requires constant management, content creation, or coding, you may need to connect to the server and content management service more often. The best solution for creating a tighter network could be a dedicated/fixed IP address.
If you make your IP address static and set to your device, you can connect to the CMS from any location and do not create any additional issues for the server or network manager that needs to monitor connections and activities. VPN software providers like can help you with such settings and offer the option to control the online reputation and manage projects easily from any part of the world.
Recover files after data-affecting malware attacks
While much of the data can be accidentally deleted due to various reasons, malware is one of the main culprits that can cause loss of pictures, documents, videos, and other important files.
More serious malware infections lead to significant data loss when your documents, system files, and images get encrypted. In particular, ransomware is is a type of malware that focuses on such functions, so your files become useless without an ability to access them.
Even though there is little to no possibility to recover after file-locking threats, some applications have features for data recovery in the system. In some cases, can also help to recover at least some portion of your data after data-locking virus infection or general cyber infection.
Questions about Worm Bagle.f
Can I safely uninstall Worm Bagle.f?
If you did not install Worm Bagle.f 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 Worm Bagle.f 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 Worm Bagle.f before it reached the app list.
Are my files on the USB drive lost?
Usually not. USB worms hide the real folders and put shortcuts with the same names in their place. After scanning the drive on a cleaned PC, open it in File Explorer, choose View > Show > Hidden items, and your folders appear, faded.
Clear their Hidden attribute in Properties, delete the shortcuts and any unknown script files, then scan once more. Copy important files to a safe place before using the drive again. If anything is missing, a data recovery tool run from the cleaned PC may still find it.
Can I just delete the file Windows Security found?
Let Windows Security handle it instead. When it finds Worm Bagle.f, choose Remove or Quarantine; the scanner also removes related startup entries and tasks that a manual delete would miss. Deleting a running file by hand often fails, and many threats restore themselves from a second copy.
After the removal, run the Microsoft Defender offline scan, which works before Windows starts and catches parts that hide while Windows runs. Then check Task Scheduler for leftovers. Restart afterwards and check that the detection does not return.
The PC is still slow after removing Worm Bagle.f. What now?
Restart the PC first; some changes only take effect after a reboot. Then open Task Manager and check the Processes and Startup apps tabs for anything unfamiliar using the processor, disk or network. If something remains, run the Microsoft Defender offline scan once more.
Slowness can also come from a second infection installed alongside Worm Bagle.f, or from programs that were damaged during the clean-up. If nothing helps, back up your files and reset Windows. Copy only documents and photos before a reset, and scan the copies.
Should I scan my other computers too?
It is a good idea, even for malware that does not spread by itself. The same download, USB stick or loader may have been used on other PCs in the household, and shared folders can carry files between them.
Run a full scan followed by the Microsoft Defender offline scan on each Windows PC that shared drives or files with the infected one. Do not copy programs or installers from the infected PC until it is clean, and change Wi-Fi and router passwords if they were saved on it.
Should I reset my PC because of Worm Bagle.f?
Only if the signs point to deeper access. Reset when you see worm Bagle.f 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.
How did Worm Bagle.f get on my computer?
The route for Worm Bagle.f is not documented yet. Malware that shows worm Bagle.f in the list of installed apps usually arrives with something you ran yourself:
- a cracked program or game cheat
- a free tool from a mirror site
- a fake installer found through a search ad
- a file on a USB drive
Some infections are dropped later by a loader that was already on the PC. To find your source, sort Installed apps by install date and look at the Downloads folder for the days before the sign appeared. Remove that item as well; otherwise the same infection may come back after the clean-up.
Is Worm Bagle.f a virus?
In everyday language, yes: Worm Bagle.f is malware, a program that runs without your consent. More precisely, the reports point to a worm, based on what people saw: worm Bagle.f in the list of installed apps. It is not part of Windows and no legitimate program behaves this way while hiding from the user.
It should be removed, and the PC checked for other programs that may have come with it. Because there is no public analysis yet, we cannot list everything it does; the removal plan in this guide is written to cover the usual places this kind of malware uses to start and hide.
Will Fortect remove Worm Bagle.f?
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 Worm Bagle.f, 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)