Calc file gives write error when saving as .xlsx format but saves ok as .odf (mac os 15.7.1)

[Lido]

I have a file I use monthly. Originally created in Excel, but migrated to Libre a few months ago. The past few months saved fine in the original file format I was using (.xlsx), but for some reason this month, no more complex than the last few, won’t save unless I select .odf.

Tried “as copy”, tried other locations, tried closing and reopening. I don’t really mind saving as .odf, but would like to maintain cross compatibility if I can.

The file does have formulas that link to another calc file, but as mentioned above, this hasn’t caused an issue previously. I believe I did update libre since the last time I worked with this file, but I’m not sure.

Version: 25.8.1.1 (AARCH64)
Build ID: 54047653041915e595ad4e45cccea684809c77b5
CPU threads: 12; OS: macOS 15.7.1; UI render: Skia/Metal; VCL: osx
Locale: en-US (en_US.UTF-8); UI: en-US
Calc: threaded

[mikekaganski]

1. Try to create a new empty spreadsheet document, and save as XLSX. Success means it’s not some general “can’t save XLSX”, but something more specific.
2. Take your problematic file, and start to remove parts of it, trying to save as XLSX each time, until you find a piece that gives you the trouble.
3. Submit a minimal file to a new bug report.

[Lido]

Sorry, forgot to mention that I can save other files as .xlsx, including the previous month’s version of the file.