Here are a few answers:
1) It is very possible that upgrading would solve your problem. Check out bug 40396. This was fixed in 5.0.20. ZCO continually tried to upload emails with large attachments because it wanted to put them in the Sent folder. You should consider upgrading.
2) As far as mismatched ZCO clients and ZCS servers: you are generally ok if ZCO is older than the server. You should always upgrade your servers first. We don't support newer ZCO's with older servers. Of course it's best to be matched up, and back around 5.0.7, there were some enhancements that happened on the server side that required a corresponding ZCO. But I think from 5.0.16 to 5.0.19 there weren't any of those issues. Having a 5.0.16 ZCO against a 5.0.19 server should be OK. But 5.0.16 is 4 versions old -- that's getting a bit long in the tooth.
3) To find offending mail messages: well it looked like the log said that the one with Zimbra Id 1462 was a problem (there were also some others [454 and 455]. These errors are coming from the SaxHandler, though, which means that they are being synced down from the server. To see which message 1462 is, for example, you can hit the content servlet:
http[s]://<yourserver>:<yourport>/service/content/get?id=1462&fmt=sync
If the message is already in Outlook, you can also enable the Support bar and do Open By Zimbra Id.
To find offending messages going from Outlook to Zimbra, you'd have to look in the logs and see where the processing of change records gets hung up. You can look for "processing change record", etc. But this is a little tougher.
If your editing an existing message in Outlook, then it would have a Zimbra Id, and you could use the techniques above. If it's new, then it won't, and you'll have to wade through the log file.  |