I haven’t found any reasonable place to make note of this.
I know libreoffice has limited resources. I have not found anyone else complaining about this, which is unfortunate for me, because it ensures this problem is not a priority.
Starting a few months ago, certain calc spreadsheets started taking a very long time to open.
I had thought libreoffice had locked up so I forced it closed multiple times before I accidentally let it run, and discovered that my files would open eventually.
I happened to time it once, and a file took seventeen minutes to open.
Once open, everything acts normally.
I tried several suggestions from forum members who had slow-opening files, but their files took a long time like twenty seconds. Mine was in minutes. Nothing worked.
I re-installed Windows and it fixed the problem. Temporarily.
This issue has recurred multiple times over the last few months. Sometimes it seems a particular update has caused it, but sometimes it just starts occurring with no update having taken place.
Relatively simple files are not noticeably affected. Large files with lots of lookups seem to be in common with extreme delay.