Problem with two-way sync (conflict and delete)

[BlueIceZz]

First up, I would like to say thank you for this great innovative tool that makes our lives easier.

Now to the situation of our sync we don't really understand.
We use FFS to try to sync data between two computers using the two-way sync mode. So what happened is we created a working folder on one computer (let's call it left and the other computer right). During one sync session, FFS is showing the conflict that one file is modified on both sides, but this particular file doesn't even yet exist on right side. Also FFS is sugguesting to delete some newly created files on left, because these doesn't exist on right (what we expect is naturally copying from left to right).

Any help would be much appreciated, thanks!

[Zenju]

Theory: This sounds as if after a *successful* sync, some file copy operations were undone (why? hard disk corruption? power loss?) but the sync database files (sync.ffs_db) were unaffected and are up to date.
The files that existed left only were copied over "successfully" and are now found missing on right => FFS tries to propagate the deletion. In the first case the left file was also changed externally, so there's a conflict.

[BlueIceZz]

Thanks for the reply! After some investigation, our guess would now also be a system error during the sync. Since this should not be a problem with FreeFileSync. I think this topic could be closed/deleted. :)