Unable to resize disk capacity due to non-existing snapshots

Hello!
I've been trying to update my Windows 10. It gets so far but complains that there is not enough disk space. About This Mac > Storage states there is 398.74GB of 1TB available. I checked via Parallels Control > Hardware > Hard Disk to find that it shows 64GB - I'm sure I had set the volume size a lot higher than this. I clicked Advanced > Properties and I get the warning "Unable to edit the hard disk properties because it has one or more snapshots." I click Manage Sanpshots and there are no snapshots!
Given the above, how do I change the size of the virtual disk so Windows doesn't run into disk size problems when trying to install updates?

 

AFAIR it is not possible to change virtual hard disk size if there is snapshots of this disk.
You need to delete all snapshots before change virtual disk size

 

Please note my comment above, "I click Manage Snapshots and there are no snapshots!"
There are *no* snapshots listed to be deleted. How can I delete snapshots if they aren't there?

 

DavidB22, could you generate technical data, send it to Parallels and share its id here?
It's better to do this while you see or right after warning "Unable to edit the hard disk properties because it has one or more snapshots"

 

mmika, thanks
I generated technical data and submited: 381920205

 

DavidB22, your VM does not have snapshots, but virtual disk does.
The last snapshot was taken on Sep 15 2019.
I guess you added virtual disk from some old Windows 7 VM into the new Windows 10.
Try to play with 'prl_disk_tool merge' command. You can use https://kb.parallels.com/en/122872
point 4 as example. Looks like there is a some mistake in command provided in KB.
The command for you looks like:
prl_disk_tool merge --hdd /Users/"$USER"/Documents/Parallels/Windows\ 10.pvm/Windows 7-0.hdd

 

mmika Hi
Some good news and some not so good.
I ran your instructions (thanks for those!) and tried resizing the disk but still got the error so made myself a drink. I was about to post with the result and went to check the wording of the error however now I could resize the disk!
I resized the disk to 192GB *however* on the General Tab, the disk size shows as 67.37GB (Hard Disk 66.77GB; Snapshots 0KB; Miscellaneous 99.9MB; Reclaimable 0KB)
I tried Windows Updates but it still reports insufficient room. File Explorer shows 62.9GB.
In summary, I've resized the Disk Capacity in Parallels via Hardware > Hard Disk to 192GB but this hasn't been implemented.
Have I missed another setting?

 

OK, in Windows disk management I see:
Blue - System Reserved 500MB NTFS (Healthy, System, Active, Primary Partition)
Blue - C: 62.99GB NTFS (Healthy, Boot, Page File, Crash Dump, Primary Partition)
Blue - 533MB (Healthy, Recovery Partition)
Grey - 128.00GB Unallocated

 

Latest...
Have used a partition manager to merge C: and the unallocated space (128.00GB). C: is now 190GB in Windows File Manager.
Parallels Hardware > Hard Drive still shows 192GB disk capacity. The General tab shows 67.96GB... I think I've realised this is the used figure, not the total figure ‍♂️