Why can't I start VM with plenty of free memory?

Why can't I start my VM when there is plenty of free memory? Issue #1: A number of customers has reported than VM's fail to start when there is plently of memory.  The error reported from the Hyper-V manager is displayed below.  Here I tried to start a 4GB VM when there was 7+GB free.  […]

Why can't I start my VM when there is plenty of free memory? Issue #1: A number of customers has reported than VM's fail to start when there is plently of memory.  The error reported from the Hyper-V manager is displayed below.  Here I tried to start a 4GB VM when there was 7+GB free. 

The most common cause has to do with a bug in Windows Server 2008 NUMA memory allocations.  This means you'll only hit this bug on NUMA machines (all multi-proc AMD machines are NUMA + many high end Intel based servers).  You can verify you have this bug by looking at the Task Manager reported "Cached" and "Free" memory.

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