Opening Edit Book hangs freezes

[desertdaisy]

No matter which book I try to open using the Edit Book feature in Calibre 9, the process hangs with a new window that shows the book title and EPUB version, filename, and Edit book in the title bar of the new window but the rest of window remains blank. I can quit and it doesn't freeze, but it never loads the book or gives me an error message either.

Any suggestions for why this is happening or how to fix it?

[enuddleyarbl]

There are some interesting things to try here:

https://contentbase.com/blog/calibre...k-not-opening/

Down near the bottom, he summarizes things with:

7. Quick Fix Checklist

• Confirm that the selected record contains EPUB, AZW3, or KEPUB.
• If prompted, choose the correct editable format rather than PDF, MOBI, or DOCX.
• Convert an authorized unsupported source to EPUB or AZW3 before editing.
• Test Edit book with a small, known-good EPUB.
• Check whether the editor is open off-screen or on a disconnected monitor.
• Confirm that the library file and folder are writable and available locally.
• Pause cloud synchronization only long enough to perform a controlled local test.
• Review antivirus history instead of disabling security globally.
• Start calibre with calibre --ignore-plugins to test custom plugin conflicts.
• Use calibre-debug -g or calibre-debug --edit-book for focused diagnostics.
• Create a temporary library before reinstalling or altering the original library.
• Stop troubleshooting as soon as the editor opens and saves normally.

His instructions above that seem pretty detailed.

[kovidgoyal]

Click the View menu and restore the File Browser and Preview panels.

[desertdaisy]

I used AI to help me diagnose the problem and fix it.
The problem was with the tweak_book_gui.json file, specifically window position on an external monitor.

Here's the AI summary:

The tweak_book_gui.json file was saved when Edit Book was open on your external Dell monitor (positioned to the right of your MacBook's screen). At that moment, Calibre recorded the window geometry as x=1349 — which is well outside your MacBook's 1344-pixel width.

When you later opened Edit Book without the external monitor connected, Calibre tried to restore the window at x=1349 — literally off-screen to the right. The window did open (which is why you saw the toolbar and title bars), but it rendered nowhere you could see it, and the UI thread hung trying to draw into an inaccessible viewport.

The fix was to put tweak_book_gui.json aside and have calibre regenerate the file with current screen setup.

@kovidgoyal - if there's a way to tweak Calibre's code to automatically take care of this problem in the future, I'm sure that would help other users with multiple monitors who also use the edit-book feature.

[desertdaisy]

Click the View menu and restore the File Browser and Preview panels.

I can't find the View menu, only a main toolbar View icon, but it doesn't have anything about File Browser or Preview panels. I need more help with this, please.

[JSWolf]

A feature to not try to render the windows outside of the existing monitor when there is only one monitor would be a very good idea.