I keep my hard drives relatively clutter free and for me creating a weekly partition image (and I have 3, but relatively small) takes well under that. These are saved to my second hard drive, which probably accounts for its speed as I’m not saving to an external drive.

Re your question to Lisandro:
It isn’t so much that is circumvents the problem - avast doesn’t run in safe mode - so no self-defence module running.

This is the point of safe mode very little runs in it to overcome problems (conflict, etc.) in normal mode.