What type of mail account do you have? Are you using personal folders (a
PST)? If so, was this PST created in an older version of Outlook? If that's
the case, what size is that PST file? Older versions of Outlook (2002 and
earlier) have a maximum size limit of 2 GB but can become kind of flakey
right around the 1.6 GB mark or a bit bigger. You can try to compact it if
that's the case.
Please advise.