Recently an update KB2750149 – .NET Framework 4.5 in Windows 8, Windows RT and Windows Server 2012 made available for Windows Server 2012. After installing this update on Windows Server 2012 failover cluster nodes, many customers notified that Failover Cluster Manager is crashing.
Later, Microsoft provided hotfix for overcoming this problem; you can download this hotfix from here.
Note:
This hotfix doesnt require you to restart Windows Server 2012 cluster node.
Cheers!
Azure Hybrid & Cloud Migration Blog 
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