Why do I get error message saying "Cannot open 1Password data"

I'm positive I do not have extra copies of 1Password on my computer. I'm aware of that issue from past experience. What I do have is a clone backup on an external drive. This has not been an issue for years. It is my (and yours?) speculation that this odd behavior may be related to this clone backup. But, the behavior doesn't appear to be the same as when there are multiple copies of 1Password on the internal hard drive. For example, with the external drive attached, 1P starts normally most of the time. Only on some days, I get that "permissions" error message on the first attempt to start 1P desktop. And again, it starts normally on the 2nd (or maybe 3rd) attempt. And it restarts normally the rest of that day. This, to me, does not suggest there is a conflict with the clone backup... but maybe I'm wrong.

How would I create an exception for the backup copy of 1P on my clone drive?