Calibre was communicating with Android phone, now won't

[SteveG23]

Using Windows 11 Pro, Calibre 9.7. I had cleaned off the library from my Android (Samsung A54, Android 14) phone to make sure Calibre 9.7 was managing it properly. I got the library on the desktop PC and then on the phone back to a fresh start and used Calibre to load a few dozen of my existing epubs. Then I took a bit of a break and found that the last batch of files I tried to copy hadn't gone through. I tried again, and now I consistently get the dreaded "error communicating with device." In the Details, I get:

C:\r\src\src\calibre\devices\mtp\windows\content_e numeration.cpp:855:Cannot write to file:[hr=0x80004005 wCode=0 name=unknown] Unspecified error

Calibre does read the library of files already copied to the device; just won't let me add new ones.
I have tried:
> rebooting the computer and the Android device;
> deleting driveinfo.calibre and metadata.calibre
> changing to a different cable and USB port
> making sure I can read the device folder from my computer in File Explorer before restarting Calibre

What have I not tried?

[kovidgoyal]

Thats an error trying to write a file to the device, if rebooting it and computer doesnt work then your remaining options are reset the device or use one of the wireless transfer methods.

[u100009]

I had a similar fate... I switched to a new Android phone (from old Redmi Note 10 to a 14 Pro).. All my ePub books (about 260) where transferred to the new phone by the wireless Xioami "Mi Mover" and are now sitting on the main storage of my new phone. After re-installing KOreader on the new phone too, I hoped that Calibre would recognize all my existing books on the phone without having to resend them all wirelessly, as they would show up as duplicates.. (I tried a few ones and that's what happened).
Then I tried to use the "Android Driver" to connected by USB, pointing the plugin to my folder in Windows Explorer, but that resulted in an error that nothing was found, so I disconnected the phone and restarted Calibre. But after the next Calibre connect from the device over Wifi, now all the books I had transferred (a dozen or so) are not there anymore .. gone!..

Is there any ways to tell Calibre to force scanning all the eBooks from KOreader on the phone, so the books would show up again in the 'Device' list ?

I've tried everything for a few hours now and couldn't find any useful hint on any of the usual Calibre or KOreader forums..

TiA for any suggestions that would avoid me to delete all my eBooks on the phone and re-transfer them wirelessly from Calibre.

[kovidgoyal]

You can control what folders are scanned by right clicking on the device icon in calibre and choosing configure this device.