[sciurius]

I have synched my library to a cloud (Drive) folder.
I've made some updates on the tablet.
I perform a library sync: Update server, all options checked, query user.

For the locally updated files, I get the mine/theirs dialog, and I choose "Mine".

When the synch finishes, the database is updated on the Drive folder, but no song files are transported. The hashcodes file is also untouched. Not surprisingly, a subsequent run of the library sync asks for the same files to be updated (and doesn't update them).

Analysis: There are 4 .cho files and 8 .pdf files involved.

The offending .pdf files are in the cloud folder with size zero (I don't know why, but that shouldn't matter), which is also reflected in the hashcodes files.
The mine/theirs dialog shows mine with the real size, and theirs with zero size. Even though I choose "mine" nothing happens -- no file is uploaded and its entry in the database and the hascodes files is not modified.

For the .cho files, the existing entry in the Files table is removed, and a new entry is made with exactly the same contents. So the only thing that actually changes in the (uploaded) database is the Id in the Files table.

HTH