I have an Exchange Server 5.5 running on Windows NT. I came in this morning and noticed the CPU pegging at 100% and no one can open attachments (Outlook 2000). The message is: "Cannot open one or more attachments."
I successfully restarted the server and the same thing happened. I have lots of free space on the server and mail is being delivered. I am running Groupshield on that server. I cleared out the message queue, but other than that I'm lost for possible solutions.
I suspect that you are running the 4.1.60 engine for GroupShield. This engine officially hit End of Life in August 2003 and the latest release of the 4367 DAT files on June 16th has been causing GroupShield customers to experience the same behaviour that you're experiencing. Essentially the 4367 DATs are incompatible with the old version of the engine, and you'll need to uninstall and update to the 4.3.20 or higher version of the engine. This should resolve your problem.