You have OS X 10.10.5. The application requires OS X 10.12 or later.

Hi, I did the upgrade to High Sierra and then closed down the computer. I reinstalled the trial version of Scrivener but continue to receive the message above when I try to open Scrivener. Thanks very much for any direction you can provide.

I would first double-check that the upgrade went through successfully, with the  ▸ About This Mac menu command. If you’re definitely on 10.13, then reinstall Scrivener. It could be that for whatever reason it is stuck on that error.

Thank you so much - that does seem to be the problem. Although when I go to the upgrades folder, it tells me that all upgrades are complete. I am grateful for your help - thanks again!