One further bit of info - I noticed trying it again today (to see if there were any more messages - there wasn’t) that it does actually mount the DMG, as I can see it in finder, so I copied it myself to applications, but when I try to open it, I got this:
Not sure why that is, as the package contents all look the same as normal.
I downloaded it manually, and it was fine.
OK, I see that it puts it into downloads, after I moved the one I downloaded manually. As far as I can tell, they look the same with the exception that finder shows the AWS folder it came from for the manually downloaded one, whereas the one Fire got doesn’t (and it also doesn’t get to the ‘Verifying…’ before it opens, it goes straight to the error above). Get info on each side by side doesn’t show any differences.
Done that, it says they are identical. I’ve done the same with the individual Fire apps as well, I can’t see anything different but something clearly is. I’ll try it on a different mac this evening.
Exactly the same thing on my home Mac (both have Mojave). I see it download the update, mount the DMG, then it gets stuck as above. If I try and run Fire in the mounted DMG, then it also does the “can’t be opened” routine.
This still happens, but I notice if I download it manually, I can then let Fire do the update itself. First time I’ve seen the Fire Updater app. So, it looks like the problem is only in the downloading part.