Hi, On Tue, 16 Nov 2010, Adam Tauno Williams wrote: > I think the issue you will encounter first is clients will start to fall > down when folders exceed a 'reasonable' number of messages. Common IMAP > clients I've seen start to exhibit severe performance issues beyond a > few hundred thousand messages. As far as I'm aware (the helpdesk guys know better than me so I'm parroting their reply), Outlook 2003's PST file has a limit of 2GB so if it's locally caching folders, you may run into that. If you use Outlook 2007 or later, the limit is more like 20GB. BUT, if you upgrade from 2003 and use the same PST, that PST may continue with the same 2GB limit. Apparently you might need to create a new PST file and move the mail into it¹. Some big users have been moved to Thunderbird to avoid this and to improve performance. Gavin ¹ To be honest, I haven't personally dealt with this issue, but this paraphrases the knowledge of those here who have. I'd think of it as having "[citation required]" beside it. ---- Cyrus Home Page: http://www.cyrusimap.org/ List Archives/Info: http://lists.andrew.cmu.edu/pipermail/info-cyrus/