My preferred way of disabling Windows Defender is to boot Linux, mount windows partition and rename windows defender directories to *.disabled or whatever.
Example (assuming it is mounted at /mnt/ntfs):
mv "/mnt/ntfs/Program Files/Windows Defender" "/mnt/ntfs/Program Files/Windows Defender.disabled"
mv "/mnt/ntfs/Program Files (x86)/Windows Defender" "/mnt/ntfs/Program Files (x86)/Windows Defender.disabled"
mv "/mnt/ntfs/ProgramData/Microsoft/Windows Defender" "/mnt/ntfs/ProgramData/Microsoft/Windows Defender.disabled"
Antivirus service fails to start and that's about it, no other side effects.
To revert just rename back.
I have dual boot set up, but I believe the Ubuntu USB install image supports NTFS.
Example (assuming it is mounted at /mnt/ntfs):
mv "/mnt/ntfs/Program Files/Windows Defender" "/mnt/ntfs/Program Files/Windows Defender.disabled"
mv "/mnt/ntfs/Program Files (x86)/Windows Defender" "/mnt/ntfs/Program Files (x86)/Windows Defender.disabled"
mv "/mnt/ntfs/ProgramData/Microsoft/Windows Defender" "/mnt/ntfs/ProgramData/Microsoft/Windows Defender.disabled"
Antivirus service fails to start and that's about it, no other side effects.
To revert just rename back.
I have dual boot set up, but I believe the Ubuntu USB install image supports NTFS.