lately my to-be-synced folder is no longer synchronized (in one direction, it still works in the other direction).
I have set the log to “debug data for fs”.
In the log, lines like the following appear all the time [anonymized for privacy]:
[BANT3] 15:50:54 INFO: Puller (folder "MyFolder" (ab4cd-efgh), item "Netfolder\\some_long_path\\some_folder\\another_long_path\\abcdefg.JPG"): insufficient space in basic N:\Parent_Folder
The destination folder N:\Parent_Folder is located on a network drive that Windows specifies as “3.46 GB free of 874 GB”. That’s not much, but I don’t think that this value says much about the actual free space on the network drive anyway. On the C drive, approximately 60 of 240 GB are free.
Temporary files are already hidden while open. Once finished they are unhidden and thus when the final operations fail, they stay unhidden - which is what happened in case of your case difference failures. They will be removed automatically after 24h.