I have a number of users with large mailboxes (20,000+ messages) who are experiencing issues opening and using Outlook. I have asked them to reduce the size of their mailboxes (which they say they cannot do) and increased the resources available on the mail server (a Windows 2008 64bit VM). Apart from implementing a archive policy, is there anything else I can do to alleviate this problem - they access their Outlook client through Citrix PS 4.5. Any help would be appreciated.

hi This are the options are available.. i) Go for archiving or ask the user to download the mails or atleast sent items to separate pst. ii) Allocate more space in storage to increase the performance.

hi This are the options are available.. i) Go for archiving or ask the user to download the mails or atleast sent items to separate pst. ii) Allocate more space in storage to increase the performance.

Is there a policy in your company that you have to keep the active emails? ie. for more than 14 days? if not create a archive policy to archive the emails. Other options are to make them use OWA and/or move users mailbox to a new db (short temp fix).

The performance issue is not the size of the mailbox, but the number of items in the folder. Get the users to move items out of the folder in to sub folders. While the performance of Outlook has got better, you should aim to keep below 5,000 messages in the core folders for optimum performance. 20,000 items is not a large mailbox, I have folders in my mailbox with more items. 20,000 items in a single folder on the other hand you will see issues. Simon. Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.