I have customer running Outlook 2003 client in Exchange mode. They have been working for several months with no problems. Since they travel, they thought that using "Cached Exchange Mode" would be useful.
However, they now receive the following error every 3-5 minutes:
'Microsoft Exchange Server - Sending' reported error (0x80040610) : 'The message being sent exceeds the message size established for this user.'
They do not have anything in their Outbox, and have received no reports about emails not making it to them. There is only one user impacted by this problem, and rebuilding the user's local Outlook profile and disabling "Cached Exchange Mode" does not resolve the issue.
However, I refuse to use this as the answer, since this is the first time this has ever occured, and only impacts one user. Unfortunately, this issue will not disappear, regardless of the time of day, offline/online/cached mode, etc.
More about :sending reported error 0x80040610 message
Only that there is a cache somewhere that insists on clearing itself regardless of whether cached mode has been turned off or not.... in other words, turning off caching prevents new files being sent to the cache, but for obvious reasons the cache still wants to complete it's task.
I don't know that, just a guess. Of course, some undiscovered virus could do something like that as well.
If you could discover the location of my imagined cache, you might clear it using safe mode or some such.
Just wild speculation from someone that doesn't use Outlook and has never used an exchange server.