Backup stopped working

I used Windows Backup regularly for a while, then started using SyncToy. I decided to bring my Windows Backup up to date, but when I click the "Backup Now" button, the cursor just circles for a second or two, then nothing happens. No error message, no nothing.

Any ideas?

[Edit: I should add that I can make a System Image, and restroring from my existing backups works fine. I just can't make a new backup.]

Make sure synctoy didn't affect the default settings for windows backup.
Create System Image - Enable or Disable

I solved a problem with backup that I think was related to permissions on the target directory. You might try it. Navigate to the previous backup (assuming it worked once) and if you want the existing bckup rename the directory in which it resides. Then try a bckup and it should write a new directory.