So I found my way to create a chart in a powerpoint using APACHE POI and Java from scratch earlier this morning (March 7, 2024) because I have been facing the same problem with my POI-generated Excel files for over a year. Whenever I opened them, I was faced with a prompt telling me an error had occurred and the file needed to be repaired. Any charts I was drawing were gone. Then about 2 hours later, I opened another spreadsheet generated in the same way, and all of my errors were gone and my charts appeared as expected. I confirmed that several of my previous spreadsheets now open fine as well and display everything they are supposed to - some of which I created as recently as earlier today and which were not working mere hours ago.
I made absolutely no changes to my workflow, or package versions. The nature of the data is identical across all my workbooks/files.
My best guess is that some sort of fix was pushed to Office 365 and delivered to my company laptop by corporate IT that just happened to coincide with the same day I finally looked into this issue... but that seems like an awfully big coincidence! I wouldn't even know where to begin to try and figure this out.
Does anyone know why POI v4.1.2 would generate Excel files incompatible with Office 365's chart indexing logic for about a year, and then suddenly start working again out of the blue?
Is it still recommended to make the change from the linked question, or will that now break my Excel files?