When I was working on my shop, and decided to publish it to roblox, the glass just vanished. I tried closing an opening, duplicating it, and separating it. Any help would be greatly appreciated. Also if this is in the wrong category or has already been mentioned, a link to the topic that fixes it or to the right category would be thanked 
Error:
Your unions got corrupted. This is something that happens to me often.
Have a solution to it? Remaking it would take a while and wont be as good
This problem is so annoying…
It’s simple, there’s no fix. ROBLOX straightup is terrible with unions and meshes in general, the best solution i know is to remake… try looking through the devforum search for more… this has been complained about before.
Sorry about this. 
So true. @thismeenswar The only thing I have seen someone said that works is copying everything and pasting it into a new world. But I doubt this will work.
Well thanks for telling me, I’ll try copying it but if it doesn’t work I’ll just remake as jv has said.
This has happened to me on numerous occasions at the most annoying times.
I have found negating/separating sometimes works for me, but that would push your progress back a bit.
Hopefully this helps
This happened a couple of times to me, the solution that always works on this (for me) is separate then union again
I have researched this topic immensely and I have discovered two methods to fix this.
Method 1:
Credits to XAXA for first applying this method.
Method 2:
You click the union then press Ctrl+N.
Thanks for the suggestions, unfortunately they don’t work.
I am deeply sorry to inform you what your union is corrupted. You are now forced to re-make it entirely.
This is just a minor glitch as part of Roblox, I usually fix this error simply by exiting and rejoining Studio, if that does not work there might be a chance it happens due to a large amount of parts unioned together. If so you should probably avoid that because it can cause studio to crash and you will lose any progress that was not saved.
There is no fix sadly 
Attempt to exit studio than rejoin to fix this issue, Always works for me but not sure about others.
In most cases, this issue only happens in studio, so just ignore it if the union in question is minor, as it will appear properly in game. If you want to edit its position, you could install the Show Decomposition Geometry plugin to see its collision mesh.
It happened alot of times with me and the best solution i know for this is to publish the union as a model immediately after you make it. so, if by any chance the union in your game got corrupted you can just import the published union back.
