Hi Tom,
As none of the experts have answered, I thought I'd take a stab at it. We had similar problems & after researching it I came up with the following.
Firstly, you don't say if it's all your users or what versions of outlook they are using, how many rules they currently have, if these are client or server-based, etc ?but here is the general info as I saved it then:
1.) Space ...
Disk space is not an issue. Rules are stored on the exchange server separately for each user. The sizelimit within the Exchange message store is 32k. This cannot be modified.
Rules are made up of two basic things (plus all the other "transparent" bits" which are more or less the same for each rule). Conditions/Instructions and Addresses. If a rule is simple and only contains one address, then you can have about 50 rules, the moment you add lists of addresses (to forward to, etc) or complicate the instruction/condition set, the size increases dramatically.
To save space you can either reduce the number of rules (delete redundant or seldom used ones), or simplify them. Replace lists of addresses with a Global Address list based distribution list (client based distribution lists get expanded & take up space anyway).
2.) Error ?
If you have a condition based on an address in a Bcc field you get this error when trying to save it as a server rule. It is an incorrect error message. Never include a Bcc address as it is disallowed for security reasons.
Technet Articles: Q241325, Q218316, Q218418, Q236088, Q236089
Hope this helps,
Peter Bellis
IT dogsbody
Job Title: ?Hey you!?