Microsoft has released a fix for the Exchange Y2K22 bug that disrupted email delivery

Microsoft released a fix over the weekend to resolve an issue that caused email messages to become trapped on its Exchange Server platforms around the turn of the year, which it blamed on a date validation problem.

“The issue is associated with a date check failure with the new year, and it [is] not a failure of the [antivirus] engine itself,” Microsoft wrote in a blog post. “This isn’t a problem with malware scanning or the malware engine, and it has nothing to do with security. The malware engine is crashing due to version validation against the signature file, resulting in messages being stuck in transport queues.”

Microsoft details the problem’s solution in its blog post, which requires administrators to either manually execute the change or use an automated script. The post also includes a comprehensive FAQ, indicating that administrators need “some time” to implement the remedy. It may take some time for the messages to reach their target recipients’ inboxes, depending on how many emails are delayed in the queue.

To address the Y2K22 bug, Microsoft recommends that clients download “Reset-ScanEngineVersion.ps1,” a PowerShell-based scan engine reset script that may be run on each Exchange mailbox server that downloads antimalware upgrades. It is worth noting that the upgrade also brings the engine’s version number up to 2112330001.

“Microsoft fully supports the newly improved scanning engine,” the company stated. “The scanning engine version was not rolled back; rather, it was rolled forward into this new sequence, as we need to work on this sequence in the long run. In this new process, the scanning engine will continue to receive updates.”