Syncthing does not synchronize “eml” files.
This problem occurs from several PCs.
Example: File name: Windows Mail\Storage Folders\Sent Items\7FFD1D84-000001F9.eml (not synchronized)
Version Information
Syncthing Version: 0.14.44
Synctrayzor Version: 1.1.18
OS Version: Windows 10 in all PCs
Syncthing does not care about file extensions, so that alone can’t be the issue. Do you have any indication in the web UI about those files (failed items)?