LabVIEW: Generic file I/O error - VIs missing when loading top-level VI.

[caleyjag]

I'm aware of some of the other threads with this same error dialogue, but I'm not sure the context is the same as mine.

I'm having a problem where a previously healthy library has now stopped loading correctly. 

When I try and load my top-level function, I get the 'Generic file I/O error.' (see attached image).  When I dig in, I find two sub-VIs, three layers down are missing sub-vis. This is strange because all relevant sub-VIs are stored in the same library. I cross-checked the paths for each sub-VI and they are all in the right place. 

If I manually 'replace' the missing sub-VI (question mark placeholder) with the appropriate sub-VI from the library, the application will function normally. I can save it, and everything seems to be fine. However if I close out LabVIEW and re-open the application, the same problems appear again. 

Very frustrating problem and I'm kind of losing my mind. 

I'm assuming the fix might be to copy/paste code into a new, fresh sub-VI with a new name and link to that instead, but I'd like to understand what happened.

Note: as far as I can tell I am not suffering from filename length issues - I'm storing locally and the filenames are short, without forbidden characters. I am using SVN Tortoise for backup. I'm not sure if that is relevant. I also migrated this application from 64-bit to 32-bit, although this error started appearing more recently than the migration.

[A_Hint_From_Trent]

It seems that LabVIEW is overwriting the reference to where these specific Sub-VIs are stored. So one way we can avoid this is if it is consistently the same Sub-VIs that are being mis-referenced, you could copy those Sub-VIs into your LabVIEW project and reference the Sub-VIs from here. This way when you save your project, the Sub-VIs will be saved locally and you will not have to continue to replace them each time you close out of LabVIEW. 

[caleyjag]

Seems like it something was corrupted in the .llb file. I tried moving the problem sub-VIs to a project-based solution above but that didn't work as long as I continued to reference other VIs from the .llb file (the problem just evolved to other sub-VIs in the llb file - kinda odd behaviour.)  In the end recovering all the contents of the .llb file by copying/pasting all items to a new, regular folder has solved the issue.