I have over 1,700 items in my June E-mail folder in Outlook 2013. When I try to select them all or individually, I get the following error "The operation failed. The messaging interfaces have returned an unknown error. If the problem persists, restart Outlook".
I have already tried the inbox repair,
I have tried to delete one at a time
I tried folder cleanup and empty folder and they all have the same results.
I even tried to move the items to another folder, they do move but they don't delete from the Junk E-mail folder.