Reduce size of Windows VM hard disk ?

It looks like you already got rid of it. The Windows 10 Configuration page shows the size as 181 GB, so it's already shrunk. (You don't actually get 76 GB back on your main Macintosh HD partition; this just prevents your Windows VM from using 256 GB (it'll stop at 180 GB; it' currently 119.7 GB, which matches both your Configuration main page, and Disk Management showing how much of C: is used).
 
George S said:
It looks like you already got rid of it. The Windows 10 Configuration page shows the size as 181 GB, so it's already shrunk. (You don't actually get 76 GB back on your main Macintosh HD partition; this just prevents your Windows VM from using 256 GB (it'll stop at 180 GB; it' currently 119.7 GB, which matches both your Configuration main page, and Disk Management showing how much of C: is used).
Click to expand...

Ah, I thought this would give me back the space on my Macintosh HD, which is constantly out of space.... Anything I can do to do that aside from deleting Parallels and reinstalling it with a smaller partition?
 
That Windows VM's virtual drive C: has 120 GB of stuff installed in it. Uninstall/delete/clean out temp folders in Windows to get it from using 120 GB down to something sane (it shouldn't be using more than 32 GB with the OS and some apps), then win Windows says it's only using say 40 GB, shut down Windows, and the VM's config main page should say 40 GB used and 80 GB reclaimable. Click Reclaim, wait, and the Mac drive should get 80 GB back.
 
George S said:
* I FOUND THE CAUSE AND SOLUTION! *

Short answer: Parallels can only remove unallocated space from the end of the drive. Shrink the volume in Windows first, make sure the free space is at the end of the drive (no extra partitions are at the end), then you can reduce the VM disk size. Below is my original reply, adding information as I tested:

I have the same issue as Matthew, and I'm sad that 3 pages later, there was no answer, not even a "We know it's broken, sorry." VM setting's General tab says Total size 40.1 GB; .PVM file is 43.1 GB. In the Hardware tab, Hard Disk shows Disk capacity 256 GB; clicking Properties also shows Size: 256 GB, Expanding disk is checked, Split the disk image into 2GB files is unchecked. Attempting to reduce the size (say 64 GB or 128 GB) and clicking Apply gives a warning that resizing is bad if you lose power. I click Continue, a progress bar shows 100% immediately, then the slider jumps from 64/128 GB back up to 256 GB.

I tried shrinking the Windows volume inside Windows 10 (I reduced it from 261144 MB to 64536 MB in 32768 MB chunks, (larger shrink values returned an error that there wasn't enough disk space available to complete the request), then shutting down and shrinking the VM disk capacity, and it STILL didn't reduce (possibly because Windows somehow has 4 partitions on the VM: 100 MB OEM, 100 MB EFI, the main NTFS one that I just shrank, the free space I just created, and then a 468 MB OEM partition. If that didn't exist or could be moved, and the Unallocated space was at the end, then perhaps Parallels could reduce the reported size.

(Note to others, this might be a possible workaround - at least now Windows won't think there's 256 GB of free space (which is more than I even have free on the host Mac machine), and it therefore won't use up all the Mac's space with an expanding PVM file.)

I then installed AOMEI Partition Assistant (freeware) in the Windows VM, and moved the 2nd OEM partition (changed free space before/after from 192/0 GB to 0/192 GB) to move the free space to the end of the drive. I then shut down and try reducing VM disk size again; this time it took a couple seconds to complete, and kept the smaller size! (If you can't install extra software, the other option would be to delete the trailing OEM partition if you're sure it's not needed.)
Click to expand...

Thanks dude, this worked!
 
Hi, I have accidentally allocated 1TB of hard disk space for the virtual machine. As a result of this the hard disk space cannot be increased. My question therefore, whether it is possible to decrease this to 500GB or to reverse the allocation altogether?
Hope someone has a solution as Parallels support has none.
Thanks.
Herbie S.
 
HerMar said:
Hi, I have accidentally allocated 1TB of hard disk space for the virtual machine. As a result of this the hard disk space cannot be increased. My question therefore, whether it is possible to decrease this to 500GB or to reverse the allocation altogether?
Hope someone has a solution as Parallels support has none.
Thanks.
Herbie S.
Click to expand...
Have you tried the steps suggested in this post?
 
On my bloody Win10 VM seemed to be having system restore points active and eating space after each update :-(
1. "Star" button -> Settings -> find and run "Storage"
2. Click on you C: partition - mine was 43GB of max 256
3. Click on "System & reserved"
4. Scroll down to "System restore" - I had almost 10GB used in system restore points
There is a button "Manage system restore"
You will get a popup window "System properties" opened on tab "System protection".
You can press the "Configure" button and see the allocated space (Current usage), you have "Max Usage" settings.
I decided to select "Disable system protection" and delete the restore points (there is a button on bottom right), as far as I have a regular backups of the VM files.
It's YOURS DECISION, but this gave me back 10G of 40G.
 
AlexanderS32 said:
On my bloody Win10 VM seemed to be having system restore points active and eating space after each update :-(
1. "Star" button -> Settings -> find and run "Storage"
2. Click on you C: partition - mine was 43GB of max 256
3. Click on "System & reserved"
4. Scroll down to "System restore" - I had almost 10GB used in system restore points
There is a button "Manage system restore"
You will get a popup window "System properties" opened on tab "System protection".
You can press the "Configure" button and see the allocated space (Current usage), you have "Max Usage" settings.
I decided to select "Disable system protection" and delete the restore points (there is a button on bottom right), as far as I have a regular backups of the VM files.
It's YOURS DECISION, but this gave me back 10G of 40G.
Click to expand...
This helped, thank you! My .pvm file went from 28 GB to 15 GB :-)

Still, I'm looking to switch from "Atril Deja Vu" to some other CAT tool - one that runs on Mac OS - so I won't need Windows at all any more. I love Deja Vu and have used it for almost 20 years now, but I switched to "Mac only" 5 years ago and I'm tired of wrestling with Parallels.
 
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