Microsoft recently published a new list for the recommended hotfixes, updates, and known solutions for Windows Server 2012 R2 Hyper-V environments. These are hotfixes specific to known problems that are not fixed by the monthly Windows update cycle. I often see that hotfixes are overlooked by server administrators which can cause unnecessary pain. I recommend reading each description carefully to see if the hotfix applies to your specific configuration, so don’t just download and install all of them. Take some time, write a script and update your servers as required.
It can save you a lot of trouble!
All hotfix lists
Recommended hotfixes, updates, and known solutions for Windows Server 2012 R2 Hyper-V environments
Recommended hotfixes, updates, and known solutions for Windows Server 2012 R2 Hyper-V Network Virtualization (HNV) environments (includes VMM)
Recommended hotfixes and updates for Windows Server 2012 R2-based failover clusters