calibre won't start (v6.15.1, Windows 11 pro)

[Bertrand]

I have a new computer (Windows 11) since a few weeks, on which I reinstalled calibre.
And I immediately have had these problems :

- After the installation, I got a window telling me that I have to restart my computer. I've never seen that with calibre before.
- After restarting, I have to click multiple times on the icon before calibre starts.


- If I don't restart the computer, this is what I get when I run calibre-debug -g

Spoiler:

C:\Users\admin>calibre-debug -g
Python path configuration:
  PYTHONHOME = (not set)
  PYTHONPATH = (not set)
  program name = 'C:\Program Files\Calibre2\calibre-debug.exe'
  isolated = 1
  environment = 0
  user site = 0
  import site = 1
  sys._base_executable = 'C:\\Program Files\\Calibre2\\calibre-debug.exe'
  sys.base_prefix = ''
  sys.base_exec_prefix = ''
  sys.platlibdir = 'lib'
  sys.executable = 'C:\\Program Files\\Calibre2\\calibre-debug.exe'
  sys.prefix = ''
  sys.exec_prefix = ''
  sys.path = [
  ]
Fatal Python error: init_fs_encoding: failed to get the Python codec of the filesystem encoding
Python runtime state: core initialized
Traceback (most recent call last):
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "bypy-importer.py", line 275, in exec_module
  File "bypy-importer.py", line 63, in get_module_code
ValueError: bad marshal data (unknown type code)

Extension modules: bypy_frozen_importer (total: 1)

Another debug log (and calibre starts normally after that) :

Spoiler:

C:\Users\admin>calibre-debug -g
calibre 6.15.1  embedded-python: True
Windows-10-10.0.22621-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.22621')
Python 3.10.1
Windows: ('10', '10.0.22621', 'SP0', 'Multiprocessor Free')
Interface language: fr
Successfully initialized third party plugins: Action Chains (1, 18, 6) && Comments Cleaner (1, 10, 0) && Count Pages (1, 13, 0) && EpubCheck (0, 2, 4) && Extract ISBN (1, 6, 0) && Favourites Menu (1, 3, 0) && Find Duplicates (1, 10, 8) && Kobo Books (1, 9, 2) && KoboTouchExtended (3, 6, 3) && Modify ePub (1, 8, 1) && Open With (1, 8, 1) && Quality Check (1, 13, 4) && View Manager (1, 10, 2) && Walk Search History (1, 5, 3)
QPA platform: windows
devicePixelRatio: 1.0
logicalDpi: 96.0 x 96.0
physicalDpi: 81.55183946488295 x 81.64285714285714
ApplicationPaletteChange event ignored
Using calibre Qt style: True
[0.00] Starting up...
[0.00] Initializing db...
[0.70] db initialized
[0.72] Constructing main UI...
qt.gui.imageio: libpng warning: iCCP: known incorrect sRGB profile
qt.gui.imageio: libpng warning: iCCP: known incorrect sRGB profile
qt.gui.imageio: libpng warning: iCCP: known incorrect sRGB profile
[3.91] main UI initialized...
[3.91] Started up in 3.91 seconds with 12978 books
Action chains: _get_plugins_resources(): start
Action Chains: _get_plugins_resources(): finished
Action chains: formulas: running on_templates_update()
Action chains: _call_plugins_on_modules_update(): start
Action Chains: _call_plugins_on_modules_update(): finished
Starting QuickView

What's going on ?

Thanks.

[kovidgoyal]

you have something interfering with calibre. exclude the calibre installation folder from antivirus, file sync, etc.