Hi there! Sorry to confront you with some big red text like this, but you need to know that at this time, members of the WeTransfer Support team can't assist you with any issues related to our Mac app.
The app is still available to download, and should function as expected, but if something starts going haywire, we're not going to be in a position to help out. Sorry to disappoint!
With the WeTransfer Mac app, it is possible to set the expiry date of your transfer if you are logged into your Pro account.
Firstly, click the WE icon to open up the Mac app and then click the gear icon in the top right hand corner. Then from this list, choose Preferences.
In the Preferences panel, you will see an option to set the "Delete transfers after" date. All transfers sent using your Mac app while logged into Pro will have this default expiry date that you set.