owdi said:
There's the actual error,

0xc03a0014
A virtual disk support provider for the specified file was not found
You could try specifying the storage type, maybe something is messed up with ISO extensions...

Mount-DiskImage -ImagePath "D:\backup.ISO" -StorageType ISO

If that fails, run this to get clearer info about the error

$Error[0].CategoryInfo

Hey owdi. I fortunately had this issue fixed as a result of upgrading my windows to 1903.

Thanks for the suggestion. I'm sure it will help someone else who googles this issue.

cheers