[vikarti]

hi,
Windows 11
large (approx 30k books, approx 110 Gb) library in Calibre.
Calibre Companion 5.4.4.20 (412)(last one).
Calibre's library itself in Dropbox. Automatic online-only mode/smart sync is not enabled
Several devices with CC.
First connect to cloud library is ok.
If calibre is not shutdown at this thime - next one from some device or other devices(!) is not - says database is damaged and show library selection dialog except there is nothing to select. Only 'reset cloud connection' on all devices and reconnect helps.
If Calibre is shutdown at this time - everything works. usually. until next day.

How to fix this?
local library on microsd doesn't look like option (CC can't connect at all - can't open it due to size, it can open smaller versions).
Dropping CC is not preferred option(I arleady use Bookfusion as secondary solution but it's still doesn't have everything necessary).