Hello,
I had same problem.
I try the following things , and I had solved.
1. move datastore
I think the virtual machine have mismatch datastore statement.
So I tried storage vMotion to another datastore, and back to original datastore.
After that , Some virtual machine solved vMotion problem.
2. use VSS
In my case , problem virtual machine use VDS, So , I migrate to VSS from VDS.
Some virtual machine solved vMotion problem.
I hope for your help
Thanks,