I’m not familiar with this error message. Could you please look inside the log file if there is a more detailed description of the error?
That’s really weird because this should actually work. A Cryptomator vault is actually just a folder. You can rename the folder or even move the folder to another location. Well, you can’t really do that while Cryptomator is running because it won’t find the new location. In that case, you have to remove the vault from the vaults list in Cryptomator (by pressing the “-” button) and re-add it from the new location (by pressing the “+” button and selecting “Open Existing Vault”).