Important Notice About .NET Framework 4.6.1 And Microsoft Exchange Server Compatibility

By Mark Farish, Senior Systems Engineer

Microsoft recently issued a notice that .NET Framework 4.6.1 is available and is a recommended update in Windows Update. However, this version of .NET Framework is not compatible with any supported versions of Exchange Server.

It is important that environments running Microsoft Exchange avoid installing .NET Framework 4.6.1, or any version of .NET Framework that is currently not supported by Exchange Server. If Microsoft updates are deployed using WSUS or other patch distribution methodologies, it is recommended that this update be explicitly excluded from Exchange servers.

Please reference the Exchange Server Supportability Matrix for supported component versions. If .NET Framework 4.6.1 has already been deployed to an Exchange environment, please follow the guidelines in this Microsoft TechNet blog for safe removal and blockage.

If you have any questions or require guidance removing .NET Framework 4.6.1 from your Microsoft Exchange Servers, please contact us at service@helient.com.

Note: The Microsoft Skype for Business team also recommends delaying the deployment of .NET Framework 4.6.1 to Lync/Skype for Business servers. Please read more about this recommendation here.

For more information about this specific notice, please see the following articles:

https://support.microsoft.com/en-us/kb/3095369 – Mailboxes are quarantined and databases fail over unexpectedly in Exchange Server 2013

https://support.microsoft.com/en-us/kb/3133990 – How to temporarily block the installation of the .NET Framework 4.6.1

http://www.expta.com/2016/02/how-to-uninstall-net-framework-461.html – How to Uninstall .NET Framework 4.6.1 by Jeff Guillet

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