Solved! Error 1400 occurred at Invoke Node in AB_Engine_Find_Unreferenced_Library_Members.vi->...

[auspex]

While writing this post, it seems I solved the problem. I'm still posting this in case it's useful to someone else, as I could find no discussion of the problem.

Since seemingly recovering from a catastrophic attempt to switch to a packed project library with the actor framework, I'm getting this error message when I try to build:

Error 1400 occurred at Invoke Node in AB_Engine_Find_Unreferenced_Library_Members.vi->AB_Source_Library.lvclass:Copy_SourceItem.vi->AB_Build.lvclass:Copy_Files.vi->AB_Application.lvclass:Copy_Files.vi->AB_EXE.lvclass:Copy_Files.vi->AB_Build.lvclass:Build.vi->AB_Application.lvclass:Build.vi->AB_EXE.lvclass:Build.vi->AB_Engine_Build.vi->AB_Build_Invoke.vi->AB_Build_Invoke.vi.ProxyCaller

Possible reason(s):

LabVIEW:  Attempted to read flattened data of a LabVIEW class. The flat data could not be converted to the requested type because the flat data is not the same as the requested type nor is it the same as any child class of the requested type.

I thought I had eliminated the problem when, after starting to write a class to replace the class I believe is at fault, I was able to build. I removed the replacement class, as I did not need it. Building again worked fine. When I restarted LabVIEW after lunch, the original build problem had returned. Adding the replacement class back into the project does not eliminate the problem. Clearing the compiled object cache has no effect.

While writing this, I tried restarting one more time and noticed "path too long" (or something like that) flashed on the screen while the project was loading. I had received no errors or warning related to path length, but I figured I would try moving some items to shorten their path lengths. When I moved the suspected lvlib, I received notice of an item being loaded from a different path. It was something that shouldn't even have been in the lvlib, but nothing had indicated it was incorrectly claimed. Removing this file from the library seems to have eliminated the build error at last, though it's possible moving the files to another location and back is what did the trick.