Hangs on Initializing User Interface

[mdhuang]

Originally Posted by kovidgoyal

Most likely all that needed to be deleted was gui.jons and/or dynamic.pickle that is where window sizes/locations are stored.

Out of curiosity, I restored my original AppData folder for calibre, and verified it was indeed "gui.json"! After deleting it, Calibre can start without any problem!

[meghane_e]

Windows 10 had a few Security Definition updates a few days ago and my Calibre started with the hanging issue.

After trying some other stuff and finding this thread, I removed gui.json and global.py.json because those were the only two files updated in AppData\Roaming\Calibre since my Calibre stopped working. Doing a Windows 10 Settings>Apps>Calibre>Modify and a Repair didn't cut it. So I resorted to an uninstall/reinstall and voila! Calibre is running again.

Prior to that, I had tried uninstalling and reinstalling Calibre 4.23 and 5.9, ran an sfc scan, went through a Cleanreboot process, uninstalling and reinstalling Calibre 4.23 and 5.9 again.

All that is to say, thank goodness for this thread!!

[meghane_e]

I would just like to add that this hang has happened 2 or 3 times in the last 6 months. I noticed it after a Windows 10 Security update most recently Jan 8 and Jan 9. The only changes were in the Security Definitions.

Edit (Apr 15. 2021): Should have specified that removing the gui.json in these instances has so far always fixed this hang.