[JSWolf]

Trying to view KePub (with all the KePub plugins installed) gives me an error in both 4.23 and 5.0.1. This is from 5.0.1.

calibre, version 5.0.1
ERROR: Unhandled exception: <b>OSError</b>:[WinError 1155] No application is associated with the specified file for this operation: 'e:\\Calibre Library\\Temp\\Robert Jordan\\The Eye of the World (2243)\\The Eye of the World - Robert Jordan.kepub'

calibre 5.0.1 Portable embedded-python: True is64bit: False
Windows-10-10.0.18362-SP0 Windows ('32bit', 'WindowsPE')
32bit process running on 64bit windows
('Windows', '10', '10.0.18362')
Python 3.8.5
Windows: ('10', '10.0.18362', 'SP0', 'Multiprocessor Free')
Interface language: None
Successfully initialized third party plugins: Amazon hi-res covers (0, 1, 0) && Annotations (1, 12, 0) && BookFusion Plugin (0, 5, 3) && Count Pages (1, 10, 0) && Diaps Editing Toolbag (0, 3, 6) && EpubCheck (0, 2, 3) && EpubSplit (2, 9, 0) && Favourites Menu (1, 0, 5) && Find Duplicates (1, 7, 2) && Hyphenate This! (0, 1, 0) && Set KFX metadata (from KFX Output) (1, 44, 0) && KFX Output (1, 44, 0) && KePub Metadata Reader (3, 2, 9) && KePub Metadata Writer (3, 2, 12) && KePub Output (3, 2, 15) && KindleUnpack - The Plugin (0, 82, 3) && Kobo Books (1, 8, 0) && Kobo Utilities (2, 11, 5) && KoboTouchExtended (3, 2, 15) && Modify ePub (1, 5, 5) && Quality Check (1, 10, 1) && Reading List (1, 6, 13) && ScrambleEbook (0, 4, 5)
Traceback (most recent call last):
  File "site-packages\calibre\gui2\actions\view.py", line 130, in view_format_by_id
  File "site-packages\calibre\gui2\actions\view.py", line 186, in _view_file
  File "site-packages\calibre\gui2\actions\view.py", line 176, in _launch_viewer
  File "site-packages\calibre\gui2\__init__.py", line 1289, in open_local_file
OSError: [WinError 1155] No application is associated with the specified file for this operation: 'e:\\Calibre Library\\Temp\\Robert Jordan\\The Eye of the World (2243)\\The Eye of the World - Robert Jordan.kepub'