Cannot open application, getting this error: "The application '1Password 7.app' can't be opened."

I got the same error. What happened in my case was, I updated to 1Password 7.9.4, but something about the update failed. There was no error message (that I saw), but 1Password's icon changed to a blank, and I couldn't launch it, the same as described above.

A fresh install did indeed fix the problem—but the problem is alarming all the same! It would be nice to know what's going on here, and whether others ran into the same problem, even though the fix is simple.