After upgrading an admin Exchange server 2013, to CU7. or newer, version, running no Exchange role, but the Management Tools one, you will notice that it is nor possible to run the enable-mailbox command anymore, and you’ll get the following notification:
WARNING: An unexpected error has occurred and a Watson dump is being generated: Could not load file or assembly ‘Microsoft
.Exchange.ManagedLexRuntime.MPPGRuntime, Version=126.96.36.199, Culture=neutral, PublicKeyToken=31bf3856ad364e35′ or one of its
dependencies. The system cannot find the file specified.
Enable-mailbox : Could not load file or assembly ‘Microsoft.Exchange.ManagedLexRuntime.MPPGRuntime, Version=188.8.131.52,
Culture=neutral, PublicKeyToken=31bf3856ad364e35′ or one of its dependencies. The system cannot find the file specified.
The reason: Unlike previous versions, CU7 uses the microsoft.exchange.managedlexruntime.mppgruntime.dll with the enable-mailbox command, and that .dll doesn’t come with this kind of installations.
The resolution: Just copy the .dll, usually located in the C:\Program Files\Microsoft\Exchange Server\V15\Bin\ folder (default location) from a CAS or MBX role server, to the admin one. Be sure the servers from which you’re copying the file, is already running the CU7 version