Gold client - database cannot be read due to an invalid on disk structure

Every time I open my mail file in the Notes 8.5 client then switch to another view, I get the error message “This database cannot be read due to an invalid on disk structure.” When I close my mail file, the same error message appears twice (i.e. it pops up, I click OK, and it instantly pops up again).

I’ve tried doing a copy-style compact on my mail file, but that had no effect.

Two really strange things about this are:

The error occurs in Notes 8.5 but does not occur in 8.0.2.

Everything seems to work properly after I dismiss the error message. I can send and receive mail, work with calendar and to-do entries, etc. Nothing seems to be actually broken, but the frequent appearance of the error message is really annoying.

Also of note is that, when I first installed 8.5 beta 2 about three months ago, this error was not occurring, but it started occurring a few weeks later and persists in the gold release.

Is there anything I can do to fix this?

Subject: Fixed, but don’t know the cause

I have just run Compact and Fixup on all local databases, including the cache and desktop files. This seems to have fixed the problem, but I have no idea which local database caused it to start with.