Microsoft releases fix for disruptive Exchange Y2K22 bug

Date validation issue caused flashbacks to Y2K

Microsoft has released a fix to address the 'Y2K22' bug, which has been disrupting email delivery using on-premise Microsoft exchange servers.

As 2022 kicked off, Exchange admins worldwide found that an issue was preventing their servers from delivering emails to the intended recipients.

Soon, admins noticed an error message in the Exchange Server's Event Log:

The FIP-FS 'Microsoft' Scan Engine failed to load. PID: 23092, Error Code: 0x80004005. Error Description: Can't convert '2201010001' to long.

All sent emails were getting stuck in a queue due to the bug.

Microsoft said it was aware of the issue in a post on its Tech Community forum. The company added that the bug was caused by a date validation error in a signature file used by Exchange Server's malware scanning AV engine, but rushed to add that it was 'not a failure of the AV engine itself'.

'The version checking performed against the signature file is causing the malware engine to crash, resulting in messages being stuck in transport queues.'

The bug impacted on-premises versions of Exchange Server 2016 and Exchange Server 2019.

Many admins dubbed the glitch Y2K22 in reference to the Y2K bug, an issue that affected some computers at the start of the year 2000.

Microsoft released a fix to address the Y2K22 issue on the 1st January, requiring admins to either implement the fix manually or apply an automated PowerShell script. In either case, the fixes must be implemented on every on-premise Exchange 2016 and Exchange 2019 server inside an organisation.

When executed, the automated PowerShell script (Reset-scanEngineVersion.ps1) will stop the Microsoft Filtering Management and Microsoft Exchange Transport services, delete older AV engine files and download the new AV engine.

Microsoft warned that it could take some time for email messages to be delivered to their intended recipients, depending on how many messages are stuck in the queue.