I have a problem with a specific folder being stuck on “Scanning” forever.
This folder (c:\backup) contains 36 files, but the problematic one is a single 300GB file (all other files are much smaller).
I saw previous issues with large files, but I understood v0.12.23 should support this size, right?
You can try v0.13-beta (currently available at http://archive.syncthing.net/v0.13.0-beta.4/ ) which should work. There are some display issues on the GUI but otherwise it works well (at least for me).
That should be fine. The bottle neck is that the file needs to be rehashed when a change is detected, and then copied for modification on the other side.