I did a clean reinstall of El Cap, and I'm trying to redownload Caffeine from the MAS, and it just gives me an error and won't download. Anyone experience this before?
Just search for it in App Store and download from there instead of purchase history. Worked for me.
Still doesn't work. I imagine you never downloaded it previously.
It seems to have been discontinued in the App Store. You can still find it on their website.
But why bother? The app is old, has not been updated in years and supports neither the aesthetics of the menu bar in Yosemite and later nor Retina displays. I recommend this simple app: KeepingYouAwake. Works in the same way, without bells and whistles.
So the message is clear: You have the apps purchased, for some years untill they finally disappear. And I don't like that policy.
Then you have not been paying attention. Don’t buy in DRM-based shops. You can still download Caffeine for free from their website.