.NET 4.6.1 is now a recommended update for Microsoft server operating systems.
If you are running any version of Exchange from 2007 to 2016, know that Microsoft says .NET 4.6.1 is not compatible. Here is the Exchange Supportability Matrix on Microsoft’s site.
We are specifically seeing reports of incompatibility between the new .NET Framework 4.6.1 update and Exchange 2013.
We have blocked this update on the servers we manage that run Exchange and Microsoft says you should do the same.
Blocking the update using a registry edit is fairly simple. Here’s how to do it:
- Back up the registry.
- Start Registry Editor. To do this, click Start, type regedit in the Start Search box, and then press Enter.
- Locate and click the following subkey:HKEY_LOCAL_MACHINE\Software\Microsoft\NET Framework Setup\NDP
- After you select this subkey, point to New on the Edit menu, and then click Key.
- Type WU, and then press Enter.
- Right-click WU, point to New, and then click DWORD Value.
- Type BlockNetFramework461, and then press Enter.
- Right-click BlockNetFramework461, and then click Modify.
- In the Value data box, type 1, and then click OK.
- On the File menu, click Exit to exit Registry Editor.