My Hatred for Unbounded Volume Shadow Copies

The times they are a-changin’.

This post seems to be older than 15 years—a long time on the internet. It might be outdated.

I’ve been running a bit low on disk space the last few weeks. I thought part of might be because I was taking more photos and at 5MB a photo, those add up pretty quick. So I started moving some of my old pictures from my internal hard drive to my external hard drive. That solved the problem in the short run, but I was still running with very little space left:

So I decided to track down where all my space was going. I used the rather helpful (and free) JDiskReport and came across something interesting:

JDiskReport was only finding 74.7GB of data on my drive, even though I have 104 GB.

So I did a Google search for: windows vista drive space

I came across an article at The Problem Solver called Windows Vista and low disk space:


Anyway back to the disk space usage. When I started I was surprised but everything went well. But the C drive kept on filling up even though I wasn’t installing new software and I kept the temp directory in check. Yesterday the bar the Explorer indicating how full the disk was even turned red so some action was needed. I fired up WinDirStat, a great utility for finding where your disk space went and reported 14Gb as . That is quite a portion of a 50 Gb disk, a whoping 28%, so I decided to focus on that first. It turns out it was in use by Windows Vista System Restore.

Could this be my saving grace? The symptoms seem to fit. I checked the Shadow Copy Storage by running “vssadmin list shadowstorage” from an elevated command line:

Shadow Copy Storage association
For volume: C
Shadow Copy Storage volume: C
Used Shadow Copy Storage space: 30.113 GB
Allocated Shadow Copy Storage space: 30.364 GB
Maximum Shadow Copy Storage space: UNBOUNDED

There, ladies and gentlemen, was the grail of my quest. The used storage space was 30GB and the maximum allowed was unbounded. Who thought that an unbounded maximum storage space was a good idea? Because I sure didn’t.

Fixing the problem is pretty trivial. Just execute

vssadmin resize shadowstorage /for=c: /on=c: /maxsize=6GB

from the elevated command prompt and all your troubles will be fixed. Of course, you might need to change c: to actual drive you want to affect and you can also tweak /maxsize= to be the actual maximum size you want.

I thought 6GB was good since I don’t rely on Volume Shadow Copies for my backups (I have a different solution).

And that’s how I made 30 GB in less than 3 seconds.

There’s also some more information on vssadmin at Microsoft TechNet.