Hello @Nomad, seems you have stumbled across a bug with closing the Interface builder skill, I'll document for @DJ Sures.

okay thanks jeremie.

Are you pressing the "YES SAVE" or "NO SAVE" option when closing ARC?

dj

i click on the X to close ARC.then this message pops up,and i click OK.

When my click X, a window asks to save. Do you press Yes or No to save?

i just tested it.bolt yes or no save gifs the error.

Okay - i found the issue and fixed it for the next release of ARC

dj

thank you sir:)