It can block and remove most threats.
However, some Trojan threats can still sneak into your system and Windows Defender might fail to remove them.
Every problem has a fix.

Scroll down to get the full tutorial now!
How to Fix Windows Defender Fails to Remove Trojan Threats on Windows 10/11?
Speaking of backup, MiniTool ShadowMaker is a top choice for you.

Meanwhile, it also supports file sync and disk cloning.
Then, hitKeep Trialto enter its main interface.
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Step 2.

In theBackuppage, you’ve got the option to choose the backup source and backup destination.
Backup source go toSOURCE>Folders and Filesto selectwhat to backup.
Backup destination head toDESTINATIONto select an external hard drive or USB flash drive as the storage path.

After making your choice, click onBack Up Nowto start the processes at once.
Heres how to do it:
Step 1.
Find Windows Defender services one by one and right-tap on them to selectProperties.
Change theStart typetoAutomatic> hitStartunderService status> click onApply&OK.
In this case, its a good option to reset Windows Security.
Heres how to do it:
Step 1.
PressWin+Sto evoke the search bar.
TypeWindows Security> opt for best match > right-punch it to chooseApp options> tap onReset.
Heres how to do it:
Move 1: Enter Safe Mode
Step 1.
OpenWindows Settingsand go toUpdate & Security.
In theRecoverysection, hitRestart nowunderAdvanced startup.
Navigate toTroubleshoot>Startup options> hitRestart.
After your gear restarts, you could pressF4,F5, orF6to enable Safe Mode as per your needs.
Move 2: Perform a Full Scan
Step 1.
OpenWindows configs>Update & Security.
In theWindows Securitytab, click onVirus & threat protection>Scan options.
TickFull scanand hitScan now.
To do so:
Step 1.Download Malwarebyteson your rig.
Launch this program > hitGet started> click onScanto start the scanning.
Once it detects any threats, you’re free to selectQuarantineand then remove them.
Final Words
Is your Windows Defender unable to remove Trojan threats on your machine?
This post provides 4 ways for you to remove the identified threats and run your Windows Defender smoothly.
You dont need to try them all until this problem is solved.