[wjwieland]

Scenario:
I run Nextcloud on my server at home. My Calibre library resides on the server. I run the Calibre application on my laptop as well as the Nextcloud sync client and keep my local library synced to the server which is backed up twice a day.

To Remember:
If one keeps the Calibre library locally on ones synced laptop ( as I do ), and runs a sync client, it is important that one shut down the Nextcloud client prior to starting up the Calibre application.

Cause:
The nextcloud client notices any changes on synced file system and immediately syncs them back to the server. This puts a lock on whatever file is being modified (the sqlite db of Calibre for example), leaving the Calibre application without access to those file, thus generating an error. (Unable to write to the database).

PS:
Just a heads up in case it has not been noticed previously.... or for someone who has not found this in some other post.
Hope someone finds it helpful....