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I've been bashing my head against the proverbial wall for a couple of days now trying to understand what was corrupt in my LV project hierarchy. On the face of it, all appeared to be fine, but I was getting some very unusual errors when executing my VIs. Errors that hadn't occurred before I rearranged stuff. In my project I have a number of classes, with various inheritances and other defined relationships, and I recently moved some things around to make it, well, better organised. I ensured I didn't destroy the relationships required to maintain access to class methods etc. Indeed, after the rearrangement, there were no broken VIs, and a mass compile (for good measure) came back clean. Now, although the majority of my classes were working fine, I had a very bizarre "Out of Memory" error occurring when accessing the private data of one particular class's DVR via an in-place structure. The private data of the class is nothing more than an array of a cluster of elements. Typically the array is empty, and in the in-place structure I am combining the contents of one class's array of elements into another's. And indeed, in the above error case I had two empty classes, so the build array function had no real work to do, yet I saw some very odd behaviour. Firstly, when highlight execution was on, the array datawire from the unbundle terminal of the in-place element structure should show "#0" to indicate no elements in the array, but in fact would regularly show #84 for one, and I would never get to see the other due to the "Out of memory" error. This was very repeatable, even after rebooting my computer. Where was it getting 84 elements from!? In a generic probe place on the class itself I would see that although the class wires showed normal content (zero elements in their private data), their Value field showed an incorrect namespace entry. This class is owned by a single library, so the namespaced title is mylibrary.lvlib:myclass.lvclass. However, the probe's namespaced title was mylibrary.lvlib:sublibrary.lvlib:myclass.lvclass, where sublibrary.lvlib is a library definition that I emptied and removed a few days ago. Yes, the class used to belong inside this library, but no more. In the library project view, the class can be confirmed to live directly within mylibrary.lvlib only. sublibrary.lvlib isn't even on the file structure anymore, it's literally gone - yet LabVIEW didn't seem to recognise this conflict. After seeing this I realised there was a corruption, but I couldn't see how to properly inspect the defined class ownership properties, or influence it? There's nothing under the Properties panel accessible from the right-click menu? I wondered if dragging the class out of mylibrary.lvlib and back in again would help, but it is changing these ownerships that caused this mess in the first place, so I decided to close down LabVIEW and overwrite the myclass.lvclass file on disk with a backup from earlier that pre-dated the original move into sublibrary.lvlib. Voila, this solved my issue immediately. So I'm quite perturbed to see that a bad ownership property in a class can cause LabVIEW to keel over with very odd execution behaviour, yet otherwise believe everything is fine in the hierarchy itself. Is there a way to inspect class ownership properties throughout a project to look for inconsistencies? To validate the information already there? I already tried a mass compile and that didn't resolve it. Now, I actually want it, and some other classes, in sublibrary.lvlib, contained within mylibrary.lvlib, but I've been trying for two days to recover my project after trying this once. I wonder now if I even dare try to rearrange my classes again!