Hi,
VI corruptions like this can be caused by a variety of things. If a VI is corrupt it can be quite difficult or impossible for LabVIEW to open that file. This is a situation where there are a number of issues that all end up with the same symptom of a corrupt VI. We fix the ones that we can diagnose and in more recent versions of LabVIEW we added additional sanity checking to detect and recover from corruptions (which also helps us find ways the corruptions occur), so the suggestion by Dennis to try and open VIs in the latest version of LabVIEW is a good troubleshooting step for trying to open a corrupt VI. As mentioned, there is a tradeoff between sanity checking and performance.
These issues are often very difficult for NI R&D to reproduce, and looking at a corrupt VI does not always give much insight into how it became corrupted. We have done a lot of work to fix these issues and improve stability in LabVIEW. That being said, I would encourage you to use source code control when working on projects, not just to protect yourself from corruptions, but for all the other benefits you get from source code control.
Regards,
Jeff Peacock
Product Support Engineer | LabVIEW R&D | National Instruments | Certified LabVIEW Architect
