[normanstein]

I think so. That is, in Calibre I went to Calibre Library, then to Library Maintenance, then Check Library and then, since a few errors were found, to restore database. I got the following error message after that:

calibre, version 2.33.0
WARNING: Success: Restoring the database succeeded with some warnings click Show details to see the details. The old database was saved as: C:\Users\USER\Calibre Library\metadata_pre_restore.db

Failed to restore the books in the following folders:
C:\Users\USER\Calibre Library\A E W Mason\They Wouldnt be Chessmen (1934) (145) with error:
Traceback (most recent call last):
File "site-packages\calibre\db\restore.py", line 253, in restore_books
File "site-packages\calibre\db\cache.py", line 57, in call_func_with_lock
File "site-packages\calibre\db\cache.py", line 1985, in restore_book
File "site-packages\calibre\db\cache.py", line 1493, in create_book_entry
File "site-packages\calibre\db\backend.py", line 804, in execute
File "c:\cygwin64\home\kovid\sw\build\apsw-3.8.2-r1\src\cursor.c", line 231, in resetcursor
ConstraintError: ConstraintError: UNIQUE constraint failed: books.id

C:\Users\USER\Calibre Library\Fyodor Dostoyevsky\Demons (Russian Edition) (419) with error:
Traceback (most recent call last):
File "site-packages\calibre\db\restore.py", line 253, in restore_books
File "site-packages\calibre\db\cache.py", line 57, in call_func_with_lock
File "site-packages\calibre\db\cache.py", line 1985, in restore_book
File "site-packages\calibre\db\cache.py", line 1493, in create_book_entry
File "site-packages\calibre\db\backend.py", line 804, in execute
File "c:\cygwin64\home\kovid\sw\build\apsw-3.8.2-r1\src\cursor.c", line 231, in resetcursor
ConstraintError: ConstraintError: UNIQUE constraint failed: books.id

C:\Users\USER\Calibre Library\David Bezmozgis\The Free World_ A Novel (432) with error:
Traceback (most recent call last):
File "site-packages\calibre\db\restore.py", line 253, in restore_books
File "site-packages\calibre\db\cache.py", line 57, in call_func_with_lock
File "site-packages\calibre\db\cache.py", line 1985, in restore_book
File "site-packages\calibre\db\cache.py", line 1493, in create_book_entry
File "site-packages\calibre\db\backend.py", line 804, in execute
File "c:\cygwin64\home\kovid\sw\build\apsw-3.8.2-r1\src\cursor.c", line 231, in resetcursor
ConstraintError: ConstraintError: UNIQUE constraint failed: books.id

C:\Users\USER\Calibre Library\B. A. Shapiro\The Art Forger_ A Novel (492) with error:
Traceback (most recent call last):
File "site-packages\calibre\db\restore.py", line 253, in restore_books
File "site-packages\calibre\db\cache.py", line 57, in call_func_with_lock
File "site-packages\calibre\db\cache.py", line 1985, in restore_book
File "site-packages\calibre\db\cache.py", line 1493, in create_book_entry
File "site-packages\calibre\db\backend.py", line 804, in execute
File "c:\cygwin64\home\kovid\sw\build\apsw-3.8.2-r1\src\cursor.c", line 231, in resetcursor
ConstraintError: ConstraintError: UNIQUE constraint failed: books.id

Now I don't know what to do.

Thanks for your help.

Norman