Hi,
thanks for the help. Unfortunately, it didn't help.
I also opened the file on a different machine with a fresh install of 1.8.4 and it also crashed. Then I installed 1.8.3 as a trial and it also crashed.
But I was able to save the file again by going to a previous version and retracing the steps and changes I made.
I found two possible reasons for the crashes:
1. I had a lot of embedded pictures and after I changed them to linked assets it didn't crash on save
2. I have a lot of auto flow boxes (it's a daily planner for 2021), some of them with a lot of text. After I removed some of them and reduced the text, it would crash less often.
Still, I get a lot of crashes in connection with auto flow boxes, which I love and use often, so I hope you can find a fix for it in the next version or even a beta. It's difficult to work like this, I would very much prefer an error message to a crash of the program.