This post is mostly intended to provide a search result in the event someone comes across the same issue I did. If this type of post is not allowed please forgive me.
While trying to perform a Live Mount for a VMware VM being backed up via a connected vCenter environment, the job was failing with error description “Live Mount is supported by VMware VMs only.” Naturally I was confused because the backed up VM was in-fact a VMware VM. Googling yielded no results, hence this post.
The cause was rather simple: the job was just failing because an existing backup job was still running. Even though the VM itself was already finished being backed up, the parent job was still running on another VM. The solution was to just wait for the entire backup job to complete.
I hope this helps keep someone from panicking in the future!