Wrong Digest Error?

I keep getting a “wrong digest” error.It was present when I did the installation, the checksums on the installation download were correct.This showed up again when I updated today.Anyone have an idea what this is?http://i374.photobucket.com/albums/oo181/dixiebonsai/Screenshot%20from%202018-02-06%2017-34-03_zpsqbni7psz.png

I occasionally run into that.

When it happens, I abort the update. And then I try again after a few hours. And it usually works.

I think the explanation is this: you have connected to a mirror at a time when it is halfway updated. So there is some inconsistency in what is in that mirror. But it is usually only a temporary inconsistency.