VM failed to migrate

[#1]

I was asked one Question in my Interview last week where i was unable to answer it, kindly can any one suggest the correct answer... here is the question:

I turned on Maintenance mode in an ESX host, all the VM’s has been migrated to another host, but only one VM failed to migrate? What are the possible reasons?

[Troy_Clavell]

you may want to delete this document and re-subit as a question.

[ManjunathV]

You can give n numbers reasons...

1. For that VM, may be rule has been set, saying the VM should be same on that host only.

2. The Virtual Machine, VMDK file is located on host machine, which cause the VM failed migrate.

3. For that VM, HA has been set to Disabled may be in Virtual Machine Option.

4. Etcccc

Manjunath V