Where Did My Windows Server's Disk Space Disappear To?

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Dear [Root] Access,

My Windows Server 2022 is running out of disk space, but I can't figure out where the space is going. I've checked for large files, enabled disk quotas, and reviewed logs, but there’s still no clear culprit. Could there be hidden files or a misconfigured storage setting I'm overlooking? How do I reclaim my lost storage?

—Disk Space Detective

Dear Disk Space Detective,

It sounds like you have covered the basics. Next, I recommend checking your disk configuration. If you have a RAID array, the system may allocate some space to parity data—a normal function of fault-tolerant RAID arrays. For directly attached disks on a Windows Server, open the Disk Management Console with the DiskMgmt.msc command to review the storage configuration. If the disks reside in an external array, examine the storage configuration at the array level.

Check for a Memory Dump File

After verifying that the lost storage space isn’t due to the RAID array configuration, you can check for a memory dump file. Although you mentioned searching for large files, it’s worth checking for a memory dump. On a server, a single memory dump can consume massive amounts of space—potentially up to a terabyte if the server has a terabyte of RAM, depending on Windows’ configuration.

Related:How I Reclaimed Terabytes of Disk Space From Hyper-V

To find where Windows stores memory dump files, go to Settings > System > About, then click Advanced System Settings. In the System Properties sheet, select the Advanced tab and click Settings under Startup and Recovery. This screen lets you configure memory dump options and shows the dump file location. Systems usually store memory dumps in C:\Windows.

Check Your Shadow Copies

Next, check if shadow copies are consuming space. Shadow copies can accumulate from backups, restore, or file versioning. File versioning allows users to revert to a previous file version without a full restore, and these versions can take up quite a bit of storage.

To see how much space shadow copies are using, open a Windows Command Prompt window and enter this command:

VSSAdmin List ShadowStorage

If shadow copies consume too much storage, you can limit the space they can use or disable them entirely.

To adjust settings:

Related:Are RAM Disks a Viable Option for Hosting Hyper-V Virtual Machines?

You can also move shadow copies to a different disk if you prefer to keep using them but reduce their impact on storage.

Check for VM files

One more possible cause of low disk space, although it is a bit of a longshot, is leftover files from Hyper-V virtual machines hosted on the file server—a setup sometimes seen in smaller organizations. For example, I have seen temporary VMs used for tasks like testing backup restores.

The problem with temporary VMs is that deleting them doesn’t automatically remove their associated files. If VMs are created and deleted regularly, these orphaned VM files can accumulate and take up considerable storage space.

Try a Disk Space Analyzer

If none of the previous steps help, try using a disk space analyzer to identify what is happening to your storage space. Several free tools are available that provide more detailed insights than File Explorer.

Read more Windows storage troubleshooting tips

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