To fix the error when using VMWare standalone converter “unable to create a vss snapshot of the source volume”. You may have conflicting drive managment software.
To Confirm what you have run the below command.
vssadmin list providers
If there are 2 and you just need the Microsoft one, simply uninstall the other drive managment software.
You may also need to remove the key for the software if its not done from the install from the below location.
Remove the key that you dont need in the providers folder.