Brian Holdsworth, senior product manager for Exchange marketing at Microsoft, said the company had received four reports of problems among customers running version 5.5 of Exchange in combination with a beta version of Outlook 2003.
In each case, the Exchange server had to execute a complex set of message-handling rules that eventually caused the server to choke, affecting message processing and server availability.
Microsoft created an Exchange 5.5 patch on Thursday to fix the problem, and engineers were working on an article describing the issue for the company's Knowledge Base support site, Holdsworth said.
Outlook 2003 will be part of Office 2003, the update of the productivity softwarelater this month. Hundreds of thousands of of the software were distributed earlier this year.
Holdsworth said the issue appears to be rare, but customers experiencing problems with a combination of Exchange 5.5 and Outlook 2003 should contact Microsoft customer support to receive the patch.
"Right now, we think it's a pretty small amount of customers that have this complex set of rules built up," Holdsworth said. "As customers have an issue, they can apply that patch."