Edit ToC: Occasionally Get Errno 13 Permission Denied

[enuddleyarbl]

I'm not sure what to do with this error. Occasionally, when I do an Edit ToC on a book, I'll get an Errno 13 Permission Denied error when I leave the Edit ToC routine. The weird thing is that I can get this error even if I leave the Edit ToC process by Canceling whatever I've done (even if I've done nothing) or by accepting it with an OK. Sometimes the error will happen again if I repeat the process on the same book. Other times, it doesn't. If it does continue happening, usually I can stop it by closing and re-opening Calibre. Nothing leaps out at me as being odd in the ToC.

Since the problem doesn't happen consistently, I'm assuming it might be some process temporarily locking a file and not releasing it in a timely manner. But, I really have no idea. Here's the latest one of these errors:

calibre, version 5.32.0
ERROR: Unhandled exception: <b>PermissionError</b>:[Errno 13] Permission denied: 'C:\\Users\\Dave\\AppData\\Local\\Temp\\calibre_tovs3ri8\\k9at59y3.epub.result'

calibre 5.32 [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
Successfully initialized third party plugins: DeDRM (7, 1, 0) && GetFileName (0, 1, 1) && Goodreads (1, 5, 1) && Kobo Utilities (2, 14, 1) && KoboTouchExtended (3, 5, 4) && Modify ePub (1, 6, 3) && Quality Check (1, 11, 4)
Traceback (most recent call last):
  File "calibre\gui2\actions\toc_edit.py", line 167, in check_for_completions
PermissionError: [Errno 13] Permission denied: 'C:\\Users\\Dave\\AppData\\Local\\Temp\\calibre_tovs3ri8\\k9at59y3.epub.result'

[kovidgoyal]

https://github.com/kovidgoyal/calibr...b4183f97f5b7c0