Check the executable log files stored in %TEMP%. These provide much more insight into what is broken vs. LabVIEW's terribly vague error information displayed in the UI. Example log attached.
I spent hours using the diagram disable structure on a large piece of software to slowly narrow down the library causing the issue. Building a debug version was of no use as the VI is broken on start-up. If I'd just looked at the logs it would have saved me so much time and frustration.
Turned out to be a broken PPL, but everything was fine in the IDE (a frequent bug with LabVIEW linking to old/broken references behind the scenes even after clearing the compiled object cache).
PTS-109_BrokenVILog_2023-05-05T090328.txt