I have two Unioned parts. The first part works fine, but the identical -second one starts to throw errors that aren’t solvable but is clearly shown in the first UnionOperation to be solvable. Example:
[spoiler]
This problem also happens if I re-open the same place. The part that was previously working suddenly becomes unsolvable.
If it wouldn’t work when the place re-opened, that means that if you had unioned it together, it would have been invisible when you opened it up again 
It was still visible when I re-opened the place.
Had you unioned it together, saved with it still unioned, and came back, it would have been invisible.
That can be true, but I didn’t combine two seperate unions so this issue isn’t along the lines of that particular bug.
Doesn’t have to be two unions. If you are able to union together any two objects, but can’t union them when you reopen, then had you unioned the together and saved, it would have become an invisible union.
I don’t seem to get what you’re saying. The union in the gif is still visible after being unioned/re-opened. I know that you start to get unsolvable errors when you have a broken (invisible) UnionOperation on your hands, but the part is not broken. Something is wrong with the UnionOperation part in the gif being reloaded or copy and pasted.
Do you still have the place open?
(like, the original one that you were able to union them together in)
[quote] Do you still have the place open?
(like, the original one that you were able to union them together in) [/quote]
I don’t have the place opened anymore. I tried to Union the model I supplied in the original post and it wouldn’t Union either. It seems that, you have to finish what needs to get done with a UnionOperation without re-opening the place or copying Union, etc. Otherwise, you can’t union it anymore in some cases if it occurs.
My studio crashes mostly when I try to de-union a copied union.
Stupid when there is a small part missing for example.
Bumping this old thread because I’ve been having this issue all day.