At this time, .NET Framework 4.7 is not supported by Exchange Server. Please resist installing it on any of your systems after its release to Windows Update.
We will be sure to release additional information and update the Exchange supportability matrix when .NET Framework 4.7 becomes a supported version of .NET Framework with Exchange Server. We are working with the .NET team to ensure that Exchange customers have a smooth transition to .NET Framework 4.7, but in the meantime, delay this particular .NET update on your Exchange servers. Information on how this block can be accomplished can be found in article 4024204, How to temporarily block the installation of the .NET Framework 4.7.
It’s too late, I installed it. What do I do now?
see the complete Article : MS Technet