If your creation that you had saved had several dotts, it may be the cause of your problem. You should avoid at all costs putting dotts in the names of the creations whenever you can, use only numbers and letters.

First to fix the error we will have to close the game and steam, then we will have to do the following key combination: Windows+R and write %AppData%, then in the next menu we will click AppData:

https://gtm.steamproxy.vip/ugc/2509144569478816836/0FDC337D7A2A49714E3185232B40530A9D1AAD93/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false

Then we move to the local folder and we have to find the RoboBuild folder inside it.

We enter the saved folder and then the bots folder, then we have to search for our creation, BUT VERY IMPORTANTLY IT HAS TO START WITH .bot

Once found we will have to make a copy of this folder for security.

Once found we will have to perform the following action:
We will change the name to one that only contains letters and numbers and the same with the files that are inside, BUT ONLY CHANGING THE PART OF THE NAME

In theory, if you have followed my steps correctly, you can now start the game and your creation should come out with the new name

I hope my guide has been useful to you, if not, you can try to contact me through steam and I will try to provide a solution to your problem.

thanks for continuing to play this game :)