Thoughts on SQL Server 2022 CU23 and SQL Server 2025 CU1 - Database Mail Issue After Patching

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#sql-server #patching #bug

if you patch SQL Server to the latest CU immediately, you may want to pause it.

The latest updates for SQL Server 2022 CU23 and SQL Server 2025 CU1 that was released on 15th of January, introduced an issue where Database Mail stops working.

Database Mail stops working after updating

Database Mail stops working after you install this cumulative update. You might see the following error message:

Could not load file or assembly ‘Microsoft.SqlServer.DatabaseMail.XEvents, Version=17.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91’ or one of its dependencies. The system cannot find the file specified.

If you use Database Mail and already downloaded this update, don’t install it until a fix is available.

If you already installed this update, uninstall it to restore Database Mail functionality.

Shortly after the release, Bob Ward from Microsoft posted online confirming there’s a problem with the latest CU. Good that it’s acknowledged but not great if you already patched production.

what’s frustating is that this kind of bug is still happening in 2026. and in many cases, it feels avoidable. to be fair, if you look through the CU notes, there are a lot of vaulable fixes in there. It is clearly they are doing a lot of work in the background and get the fixes out to the public asap.

But maybe that speed is part of the problem.

This feels like a case where internal processes need another look.

My rule of thumb for patching:

  • stay 1 to 2 CUs behind
  • patch immediately only for zero-days or bugs that affect your environments
  • apply the patch first in lower environment for 2 weeks

Let someone else be the early adopter. Patching shouldn’t cost you sleep.

Dan Co

SQL Server Specialist.