Exchange 2007 / 2010 rules size limit and how to increase it

 

By default Exchange 2007 / 2010 rule size is 64 KB but is expandable to 256 KB.  Exchange 2003’s limit was 32 KB.  Use the cmdlet below in Exchange Powershell to make the changes.

To set the rules quota to 256kb for the user dummy run
[PS] C:\>get-mailbox dummy|set-mailbox -rulesquota 256kb

To make sure that the user has got the new rules size run
[PS] C:\>get-mailbox dummy|fl rulesquota

It should return
RulesQuota : 256KB

To set the quota for all users run
[PS] C:\>get-mailbox|set-mailbox -rulesquota 256kb

To get the quota of all users run
[PS] C:\>get-mailbox|fl rulesquota, alias

Source

http://www.slipstick.com/rules/32kb.asp
http://www.mattiasholm.com/node/23