Cannot complete Flash installation because Chrome is open. I do not know why this prompt exists as I have closed every app including Chrome and related.
Are you using windows machine? Can you check in task manager if any chrome related process is running.
it's possible some other process is reporting itself as Chrome. View task manager and select to view processes for all users. Locate the process identifying itself as Chrome and terminate it.
I had a similar problem. Even after rebooting, I would get an error message saying Chrome was running.
In Task Manager, I could see that Chrome wasn't a running app, however, when I scrolled down through the background processes, I found that the Chrome extensions were running! I closed those. Problem solved.