As @theducks said, that error indicates the database is corrupt. The usual solution I recommend is to sign out. The database is created from scratch during the setup process.
If calibre still has problems accessing the database, it suggests more problems. Can Windows access the device properly when it is connected? Does it show any errors? Can you write to the device? Did the sign out work and take you through the setup process? Can you try another USB port or cable?
If it isn't working, you will probably need to do a factory reset.
|