This is usually related to either playing Exalt from a different computer account than the one it was installed on originally or a problem with writing permissions on the documents folder.
Please check if you have a folder called 'Production' or 'Testing' in this directory:
To get to the home directory use the keyboard shortcuts in the Finder: Command-Shift-H.
Please manually delete them if you have one or both of these folders and try to update the client again. If that doesn't work, try switching from the top-right dropdown button on the Exalt Client between the 'Production' and 'Testing' environments and try again. Alternatively, try to restart the computer as sometimes the game process can remain running and cause this issue.
Also, try to play the game from the same computer user, on which you have installed it initially.
Or you can delete those folders, uninstall the game, create a new user account with full privileges on this computer and install Exalt again on that user to see if this works as a temporary workaround.
If none of these provided steps work please make sure to contact us with a detailed explanation of what troubleshooting steps you have attempted so we can investigate further.