Something went wrong. CSG returned error code -25

I was working on building a map when I tried to union two parts and got this message:


Figured I’d do what it asked and file a bug report.

To reproduce this issue, simply open the provided Roblox level file and attempt to union the only two parts. The same message should appear.

CSG returned error code -25.rbxl (24.1 KB)

I will note that this issue did not halt my progress much. I was able to delete the Negate part, re-create it, and get the union action to work. However, this level file appears to still have the issue and could be used to help create a fix.


Are they only normal parts or are they meshparts,etc?

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I was attempting to union a part (class Part) and a negative part (class NegativePart). Feel free to download the provided Roblox level. It consists of the two parts I was previously trying to union.

The negate part has lost history data. Could you provide details to help us figure out how this data loss can happen? e.g., Were you using Team Create? Have you performed undo operations? Did you “Save to Roblox as”? Did this happen after you re-open the place? etc.


This occurred in a place with team create turned on. I don’t believe I performed any undo operations. Can’t remember that part with 100% certainty. Sorry. However, I know I did not use “Save to Roblox as”.

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