Outlook rules are breaking when we migrate users from Exchange 2003 to 2007. By Eriq VanBibber

Article by: http://www.priasoft.com/

Rules come in 2 flavors: server-side and client-only.

Most people have heard of both of these, but i find that most don't quite understand the difference.

Server-side rules are rules that do NOT require Outlook in order for the rule to work. Client-only rules require Outlook and thereby require an acutual 'client' to be running for them to work.

The reason for explaining this will come shortly.

Secondly, the main reason that rules break is due to the type of rule. Any rule that moves/copies items to a folder are likely to break. The reason is that in the context of the rule, the target folder is not stored as a name. It is stored as a MAPI EntryID (a binary identifier of a folder, much like an objectGuid in AD). When a rule is merely copied from one Exchange Org to another, the rule is broken because the folder with the same name in the target mailbox actually is a 'new' folder with a different ID.

The only way to deal with this is with software that will 'translate' the rule; meaning that the software fixes the rule to use the ID of the new folder in the target mailbox.

Client-only rules, however, are stored in a proprietary format in mailbox and so no-one (excepting microsoft outlook dev team) knows how to parse/edit these rule types, which ultimately means that if a client-only rule exists, and is a rule that copies/moves items to a folder, there's no way to fix it, except by the end user.

Now, in my 9+ years as a MAPI developer and developer of migration tools, the percentage of rules that are client-only AND move/copy to folder is very low.

One thing that can be done by end users is to export/import their rules, however, realize that the outlook team does not deal with resetting the folder IDs on import. The user still will have to fix them.

I can speak with authority on this because i developed the rules migration code in Priasoft's migration product.