Thanks Support. I have gone back and forth on this a "thousand times". Environment vs the update. Every time I think it's one something comes up and makes me think the other.

As to what happened and what they were doing has been a hair pull since they keep telling me they are not doing anything out of the ordinary and this issue seems to have arose when the upgrade (or at least the service pack) was applied.

Since they don't receive an error when posting they only find out about the corruption when the print (surprise) the Detail Listing to Excel Direct when they are reconciling accounts and they discover the error that has happened before "GL Details Missing for period x" is sitting in the Description column for one or more accounts.

They then run Integrity and obviously the error appears as the example above.

FWIW the files that I will upload to you - the good files were clean as of yesterday at noon (according to their IT person). So not exactly sure when the bad files got corrupted but obviously sometime after noon yesterday.

Thanks for looking into.