Hello,
My version of Scrivener is having downloading the updates. I’ve put up a screenshot.
Can you tell me how to work around this?
Please download the full installer from the website (or from this direct link) and install over your current 1.6.1 installation. There was a bug in the 1.6.1 updater that caused the mismatch error during the update, which will be fixed with the manual installation. Sorry for the inconvenience!
I clicked on that installer to download it and then ran it and it said that the Installer Payload Initialization failed.
Okay, downloaded the installer on the website and got the update then 
Great, I’m glad you got it sorted!