Problems with my glo and Calibre

so out of the blue calibre doesn't connect with my glo ???
no more selves, all loaded shelves empty and not readable say's my glo???

this is the report from calibre

calibre, version 0.9.37
FOUT: Fout: Fout bij communicatie met apparaat

database disk image is malformed

Traceback (most recent call last):
File "site-packages\calibre\gui2\device.py", line 85, in run
File "site-packages\calibre\gui2\device.py", line 476, in _books
File "site-packages\calibre\devices\kobo\driver.py", line 1702, in books
DatabaseError: database disk image is malformed


Any one who can help??

Thanks M Damsma