@BetterRed, @theducks and @kovidgoyal thank you for your responses.
Here is what I did today: I deleted the whole library. Then, went back to the old PC and used the Calibre Export to export the library into the external HDD. Then connected the external HDD to the new PC and started a Calibre Import from there. Everything went OK. But when I tried to modify a title I got the exact same error: "cover.jpg did not exist when this move operation was started"
Then I went on to try @BetterRed's idea. I uninstalled the 64 bit and installed they 32 bit version. And the error was still there:
Code:
calibre, version 3.8.0
ERROR: Unhandled exception: <b>ValueError</b>:The file u'C:\\Users\\erenc\\Documents\\Calibre\\<LibraryName>\\<Author>\\<Title> (Id)\\cover.jpg' did not exist when this move operation was started
calibre 3.8 embedded-python: True is64bit: False
Windows-10-10.0.15063-SP0 Windows ('32bit', 'WindowsPE')
32bit process running on 64bit windows
('Windows', '10', '10.0.15063')
Python 2.7.12+
Windows: ('10', '10.0.15063', 'SP0', u'Multiprocessor Free')
Interface language: None
Successfully initialized third party plugins: Find Duplicates (1, 6, 2) && Open With (1, 5, 9)
Traceback (most recent call last):
File "site-packages\calibre\gui2\metadata\single.py", line 604, in accept
File "site-packages\calibre\gui2\metadata\single.py", line 579, in apply_changes
File "site-packages\calibre\gui2\metadata\basic_widgets.py", line 220, in commit
File "site-packages\calibre\db\legacy.py", line 824, in func
File "site-packages\calibre\db\cache.py", line 62, in call_func_with_lock
File "site-packages\calibre\db\cache.py", line 1095, in set_field
File "site-packages\calibre\db\cache.py", line 1109, in update_path
File "site-packages\calibre\db\backend.py", line 1561, in update_path
File "site-packages\calibre\db\backend.py", line 1347, in copy_cover_to
File "site-packages\calibre\utils\filenames.py", line 419, in copy_path_to
ValueError: The file u'C:\\Users\\erenc\\Documents\\Calibre\\<LibraryName>\\<Author>\\<Title> (Id)\\cover.jpg' did not exist when this move operation was started
I only see this error in this library. I have two other libraries located next to this one and the work fine.