Suddenly can't save my indd file any more

So I have been working on this InDesign file for several weeks now, without any problems. It's some 180 pages long and has several stories (one per chapter). There are a handful of images in it, the rest is simply running text, with no special formattings except for lots and lots of footnotes.

Now I need to delete a line from my file, and as soon as I choose to save the file, the spinning wheel occurs. I assume this is because of a reflow of text. All I can do now is wait, and then Force Quit InDesign.

In my attempt to find a way to handle this,

• I tried using "Save as ..." and give it a new name;
• I have saved the file as .idml, opened it again, tried to save it;
• I have trashed preferences.

But none of this helps resolve the problem. So I assume the culprit is neither a corrupted file nor a buggy installation. The file is saved on my harddisk. The .idml file size is 555 KB, saved as .indd it is 4.7 MB. The good news is that so far I have not lost any data.

Surely there must be a way I can save the file and, er, simply continue working?

Thanks

Sam

Adobe InDesign 2022, 17.1

macOS Monterey (12.2.1)
Processor: 3.1 GHz Dual-Core Intel Core i7
Memory: 16 GB 1867 MHz DDR3