SQL Server 2025 Cumulative Update 1 came out last week, and I was kinda confused by the release notes. They described a couple dozen fixed issues, and the list seemed really short for a CU1.

However, the more I dug into it, the weirder things got. For example, there were several new DMVs added – which is normally a pretty big deal, something to be celebrated in the release notes – but they weren’t mentioned in the release notes. One of the DMVs wasn’t even documented. So I didn’t blog to tell you about CU1, dear reader, because something about it seemed fishy.

Sure enough, Microsoft just pulled 2025 CU1 and 2022 CU23 because of an issue with database mail:

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.

If you’ve already installed one of the affected CUs, and you need an emergency workaround fix until you can uninstall the Cumulative Update, check out this learn.microsoft.com post. Down in the answers, there’s a workaround with a PowerShell script to poll for unsent emails and send them manually. (I haven’t used this personally so I can’t vouch for it, but hey, any port in a storm.)