When installing Hyper-v clusters in either Windows 2008r2 SP1 or Windows 2012, it's really important to keep up to date with all the hotfixes. Oddly enough you would think that Windows update would do this. But that's not always the case.
Here is a list of hotfixes from the Cluster team.
Here is a list of hotfixes from the Hyper-V team.
To see if you have a hotfix installed or not you can use this command. In this example I am searching for a hotfixed numbered 2813630 & 2796995
wmic qfe list full | find "2813630"
wmic qfe list full | find "2796995" - ODX hotfix
wmic qfe list full | find "2919355" - Windows 2012 R2 Update
If the return result is blank you don't have it installed.
To list all the hotfixes installed on the system use that command:
wmic qfe list full | find "KB"