CantOpenError: unable to open database file

[Morriekins]

PLEASE HELP. I don't know what I'm doing wrong but I cannot get this program to work.

calibre, version 5.14.0
ERROR: Unhandled exception: <b>CantOpenError</b>:CantOpenError: unable to open database file

calibre 5.14 [64bit] embedded-python: True is64bit: True
Windows-10-10.0.19041 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.19041')
Python 3.8.5
Windows: ('10', '10.0.19041', '', 'Multiprocessor Free')
Interface language: None
Traceback (most recent call last):
File "calibre\gui2\actions\view.py", line 114, in view_historical
File "calibre\gui2\actions\view.py", line 324, in _view_calibre_books
File "calibre\gui2\actions\view.py", line 151, in view_format_by_id
File "calibre\gui2\actions\view.py", line 339, in update_history
File "calibre\db\cache.py", line 72, in call_func_with_lock
File "calibre\db\cache.py", line 659, in set_pref
File "calibre\db\backend.py", line 139, in set
File "calibre\db\backend.py", line 133, in __setitem__
File "calibre\db\backend.py", line 920, in execute
apsw.CantOpenError: CantOpenError: unable to open database file
Running a 64 bit Windows 10 with library located on attached external drive.

[theducks]

I suspect you security software is protecting you from possible vicious threats on external drives.

OK I laid it on a bit thick, but foreign (portable) drives are still a way the malware gets spread.
Configure an exception in your security for the Library folder