Maximum number of rules per folder in the Inbox or in a public folder in Exchange Server 2003, Exchange 2000, and Exchange Server 5.5

Microsoft Exchange Server can define rules to automatically operate on messages in the Inbox or in a public folder. There is a 32-kilobyte (KB) "packed data" memory limit for the rules on each folder in the Inbox or in a public folder. The reason for the memory limit is that the total sum of the information that is contained in a user's rules must fit in a remote procedure call (RPC).

Sometimes, you may receive the following error message when the number of rules exhausts the 32-KB memory limit:

The maximum number of rules depends on the size of the rules that are defined. Additionally, the amount of data that is required for a rule varies depending on the rule.

For example, a rule to move messages into a folder for a single recipient takes about 660 bytes. Therefore, there is no defined limit for the maximum number of rules that can be assigned to a folder. Typically, the limit is between 40 and 50 rules per folder.

For more information about the maximum number of rules per folder in the Inbox or in a public folder in Microsoft Exchange Server 2007, visit the following Microsoft Web site: