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

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: – Mailboxes are quarantined and databases fail over unexpectedly in Exchange Server 2013 – How to temporarily block the installation of the .NET Framework 4.6.1 – How to Uninstall .NET Framework 4.6.1 by Jeff Guillet

Helient is a high-end consultancy specializing in legal technology and law firm computing providing innovative and future-focused technology solutions that allow customers to maximize productivity, improve responsiveness and deliver outstanding value. The professionals that comprise Helient Systems have designed, consulted and managed legal computing environments for more than 20 years across dozens of leading AmLaw 100 & 200 firms as owners and knowledge leaders. Helient was formed to bring together the top industry talent who specialize in legal technology and the latest desktop and application virtualization solutions. For more information, please contact Steve Hatch, Chief Operating Officer at