I have Windows Live Mail 2012 running on my Windows 10 laptop and desktop.  Back from traveling I wanted to move the messages on my laptop from inboxes and sent folders to my desktop Live Mail 2012.  I normally copy the messages to a new folder on the desktop and drag the messages to a corresponding folder within it, then move them to the desktop.  This time I get an error message after 34 of 828 messages copy that reads: 

I hit continue, and then I get 89 of 828 messages copied and this error:

Two of the four accounts copy fine, but the behavior is the same in the two that generate the error.

Looking at the messages to copy the largest one is 2.7mb.

I moved all the messages from one of the errant folders to another folder within Live Mail, they moved fine, but when copied to the desktop folder generate the same two errors at the same number of message files copied.

Not sure what to try next?  Thanks!