FreeFileSync doesn't seem to want to sync

[braincramp]

Hi - I am a relative novice in using this program.

I would like to sync two folders that each have sub-folders. When I do a compare at the folder level it doesn't show any files to sync. When I compare at a sub-folder level it shows lots of files to copy.

For example when f:\a is compared to d:\a there are no files shown to sync.
When f:\a\b is compared to d:\a\b it correctly shows lots of files (over 33 MB) to sync.

This one task has worked well for over a year. I did not change any settings (at least intentionally).

I am using Version 8.9 with Windows 10 Pro.

Any help would be appreciated.

Many thanks