I purchased the program on the App store It downloads, then says “Omnigraffle” has failed to install. Please try again from the ‘Purchased’ screen". I do, and the same thing repeats. Rebooting doesn’t fix it. Moving the stub file into the trash then rebooting doesn’t fix it either.
Macbook Air, 8 gig, 400 gigs free HD space.
Other apps from the app store have installed fine and I just installed a free app as a test and that installed fine, too.