WSL2 + Dev Drive on D: without filling C:

Tested onPro (26H2) · Build 26300.9457 · x64

E2

Build

26300.9457

Edition

Pro (26H2)

Architecture

x64

Support

Lab (WSL2 + Dev Drive)

Evidence

E2Reproduced in the lab

Risk

R2Needs a restore point

Verified

2026-10-28

Test machine

PVE 9.2.2 VM 361; Windows 11 Pro 26H2 26300.9457; 8GB/4 vCPU; 128GB SATA data disk formatted as D: ReFS Dev Drive; WSL 3.0.3; Ubuntu 24.04

Page type

Task

VM 361: D: is a trusted ReFS Dev Drive, Ubuntu 24.04 runs on WSL2 kernel 6.18, and ext4.vhdx is on D:. Click to open full size.

The short answer

WSL2 stores each Linux distribution in a VHDX. By default that file lives under %LOCALAPPDATA% on C:. You can put it on D: instead, format D: as a Dev Drive, and keep C: for Windows itself.

This lab did exactly that on Windows 11 26H2:

Item	Lab result
D: volume	127.9GB ReFS, label DevDrive, trusted developer volume
WSL	3.0.3.0, default version 2
Distribution	Ubuntu 24.04 LTS
Kernel	6.18.54.1-microsoft-standard-WSL2
VHDX	D:\WSL\Ubuntu\ext4.vhdx, 1.25GB after first boot
User	dev, default in /etc/wsl.conf

But get the expectation right before you copy commands:

Dev Drive does not make Linux files faster

Microsoft’s Dev Drive FAQ is explicit: WSL runs in a VHD, and you should not expect a performance improvement when accessing Dev Drive project files from WSL. The WSL metadata mount option is not supported on ReFS, the file system Dev Drive uses. Put the VHDX and Windows-side repositories/caches on D:; keep Linux repositories inside the ext4 VHDX, not on /mnt/d.

If speed is the only goal, leaving the VHDX on C: is simpler. This layout is about capacity isolation: the VHDX and Windows-side data live on D:, while Linux files stay inside ext4.

Before you start

Check	Requirement
Windows	Windows 11 22H2 build 22621.2338 or later for Dev Drive
Free space	At least 50GB for the Dev Drive; 128GB is comfortable
Permissions	Local administrator; fsutil and disk formatting need elevation
Disk	A new or unallocated disk. Formatting destroys it
Virtualization	WSL2 needs virtualization; if Windows is itself a VM, nested virtualization must be enabled
Backup	Any existing data on the target disk is erased

Verify the disk number first

Initialize-Disk and Format-Volume erase the selected disk. Run Get-Disk and match the disk by size and model before you touch it. Do not run these commands against Disk 0 on a working PC.

Step 1 — Make D: a Dev Drive

Dev Drive is created only at format time. You cannot convert an existing NTFS volume in place, and C: cannot be a Dev Drive.

Inspect the new diskTerminal (admin)

Get-Disk | Format-Table Number,FriendlyName,PartitionStyle,OperationalStatus,Size
Get-Volume | Format-Table DriveLetter,FileSystemLabel,FileSystem,DriveType,Size

If D: is currently a CD/DVD drive, move that drive letter first. In the lab the 26H2 ISO held D:, so it was reassigned to Y: before the data disk was formatted.

Expected: The new disk is Online, RAW or uninitialized, and has the size you expected.

Initialize, partition and format as Dev DriveTerminal (admin)

Initialize-Disk -Number 1 -PartitionStyle GPT
New-Partition -DiskNumber 1 -UseMaximumSize -DriveLetter D
Format-Volume -DriveLetter D -FileSystem ReFS -NewFileSystemLabel DevDrive -DevDrive -Confirm:$false

Verify from an elevated PowerShell:

Get-Volume -DriveLetter D
fsutil devdrv query D:

Expected output includes This is a trusted developer volume. A normal, non-elevated shell can return Access is denied for fsutil; that is a permission issue, not a broken Dev Drive.

Expected: D: is ReFS, labelled DevDrive, and fsutil reports a trusted developer volume.

The Settings path is equivalent: System → Storage → Advanced storage settings → Disks & volumes → Create dev drive. The command line is easier to document and repeat.

Step 2 — Install WSL2

On a normal Windows 11 PC, the supported path is:

Install WSL without a distributionTerminal (admin)

wsl --install --no-distribution

Reboot if Setup asks. Then check:

wsl --version
wsl --status

Expected: WSL installs; a reboot may be required for Virtual Machine Platform.

This lab image had no Store WSL package

wsl --install returned exit 1 on the clean 26H2 image because the Store WSL package was absent; enabling Microsoft-Windows-Subsystem-Linux and VirtualMachinePlatform by DISM was not enough. The lab installed the official WSL 3.0.3 x64 MSI from Microsoft’s WSL releases and verified its SHA-256 against the GitHub release asset digest before installing. A normal PC should try wsl --install first; use the MSI only when the supported path is unavailable.

Step 3 — Put Ubuntu on D:

If the distribution list is reachable, one command does it:

Install Ubuntu directly to D:Terminal (admin)

wsl --install -d Ubuntu --location D:\WSL\Ubuntu --no-launch

--location must be an absolute path. --no-launch avoids the interactive first-run prompt until you are ready.

Then start it once to create your Linux user:

wsl -d Ubuntu

Expected: Ubuntu is registered and its ext4.vhdx is created under D:\WSL\Ubuntu.

If wsl --install cannot fetch the distribution list, use Ubuntu’s official rootfs and import it. This is also the reproducible path for an offline or restricted network.

Fallback: import the official Ubuntu rootfsTerminal (admin)

New-Item -ItemType Directory D:\WSL -Force
curl.exe -L -o D:\WSL\ubuntu-24.04.rootfs.tar.gz `
  https://cloud-images.ubuntu.com/wsl/releases/24.04/current/ubuntu-noble-wsl-amd64-wsl.rootfs.tar.gz

# Compare with SHA256SUMS from the same directory before importing
Get-FileHash D:\WSL\ubuntu-24.04.rootfs.tar.gz -Algorithm SHA256

wsl --import Ubuntu D:\WSL\Ubuntu D:\WSL\ubuntu-24.04.rootfs.tar.gz --version 2

Create a normal user, set it as the default, and stop the distro:

wsl -d Ubuntu -u root -e useradd -m -G sudo -s /bin/bash dev
wsl -d Ubuntu -u root -e passwd dev
wsl -d Ubuntu -u root -e bash -c "printf '[user]\ndefault=dev\n' > /etc/wsl.conf"
wsl --terminate Ubuntu

Expected: Ubuntu is registered as WSL2; the VHDX is on D:.

The lab used the fallback: the distribution list URL (raw.githubusercontent.com) was reset, so wsl --install -d Ubuntu could not run. The 24.04 rootfs was verified against Ubuntu’s SHA256SUMS before import.

Step 4 — Verify the VHDX is on D:

Check WSL version, distro version and VHDX pathTerminal (admin)

wsl --list --verbose
Get-Item D:\WSL\Ubuntu\ext4.vhdx | Select-Object FullName,Length
wsl -d Ubuntu -e bash -lc "grep PRETTY_NAME /etc/os-release; uname -r; whoami; df -h /"

Expected: VERSION is 2; the kernel ends in -microsoft-standard-WSL2; ext4.vhdx is under D:\WSL\Ubuntu.

Lab output:

NAME      STATE     VERSION
* Ubuntu  Stopped   2

PRETTY_NAME="Ubuntu 24.04 LTS"
6.18.54.1-microsoft-standard-WSL2
dev
Filesystem      Size  Used Avail Use% Mounted on
/dev/sdd       1007G  1.2G  955G   1% /

The VHDX grows on demand; the 1007G inside the distro is virtual capacity, not 1TB reserved on D:.

Step 5 — Decide what actually goes on D:

Dev Drive is for source repositories, package caches, build output and intermediate files — not for installing applications and SDKs. Keep the tools on C:; put their data on D:.

D:\
├─ Dev\                 Windows-side repositories
├─ packages\
│  ├─ npm\              npm cache for Windows Node
│  ├─ pip\              pip cache for Windows Python
│  └─ cargo\            Cargo home for Windows Rust
└─ WSL\
   └─ Ubuntu\
      └─ ext4.vhdx      Linux files live inside this VHDX

For Windows tools, redirect caches only if you actually use them:

setx /M npm_config_cache D:\packages\npm
setx /M PIP_CACHE_DIR D:\packages\pip
setx /M CARGO_HOME D:\packages\cargo

For WSL, do the opposite: keep repositories inside the Linux file system, for example ~/code, not under /mnt/d/Dev. /mnt/d is a Windows file system view; it has different permissions and is slower for Linux workloads.

Step 6 — Know the ReFS limits

Limit	What it means in practice
metadata mount option unsupported	Do not add metadata to WSL automount options for D:; Linux ownership/permissions on /mnt/d will not behave like ext4
No Linux performance gain	A VHDX on Dev Drive is still a VHD; Microsoft says not to expect Dev Drive speedups for WSL files
No application installs	Dev Drive is for project data, not SDKs/apps; keep tool installs on C:
Minimum 50GB	Smaller volumes cannot be Dev Drives
Format-time only	You cannot convert an existing NTFS D: into a Dev Drive without erasing it
Trust is per machine	Moving a Dev Drive VHD/disk to another PC loses the trusted designation until re-designated

Do not move an existing distro with this page

This is a fresh install recipe. Moving an existing WSL distribution is a different operation with its own backup and rollback requirements; it was not tested in this run.

Troubleshooting

Symptom	Likely cause	First move
HCS_E_HYPERV_NOT_INSTALLED or “virtualization is not enabled”	Virtual Machine Platform off, firmware virtualization off, or Windows is a VM without nested virtualization	Enable the Windows features; on a VM expose SVM/VT-x and SLAT to the guest. The lab needed PVE cpu: host instead of a qemu64 baseline
WSL_E_LOCAL_SYSTEM_NOT_SUPPORTED	wsl.exe was launched as SYSTEM (for example by a service/agent)	Run WSL as the logged-in user, or from an interactive scheduled task with the user’s token
WININET_E_CONNECTION_RESET while fetching the distribution list	raw.githubusercontent.com blocked or reset	Use the official Ubuntu rootfs + wsl --import path above
fsutil devdrv query returns Access is denied	Shell is not elevated	Open PowerShell as Administrator
ERROR_ALREADY_EXISTS on import	A distro named Ubuntu is still registered	wsl --unregister Ubuntu destroys its data; or import under a new name
Initialize-Disk fails	Disk is offline, read-only, or already initialized	Check Get-Disk; do not force a disk that contains data
Format-Volume -DevDrive fails	Less than 50GB unallocated, or the volume was already formatted	Create at least 50GB of unallocated space; Dev Drive must be the original format

What this page verified

Claim	Evidence
D: is a 127.9GB ReFS Dev Drive, trusted, with WdFilter attached	E2, VM 361 screenshot + fsutil devdrv query
WSL 3.0.3 runs Ubuntu 24.04 as WSL2	E2, wsl --list --verbose, kernel 6.18.54.1-microsoft-standard-WSL2
The Ubuntu VHDX is on D:	E2, D:\WSL\Ubuntu\ext4.vhdx
wsl --install Store path is not universal	E2, it failed on this image; rootfs import succeeded
Dev Drive speeds up Linux files	Not claimed; Microsoft says the opposite
Docker Desktop, VS Code, Node, Claude Code, Codex	Not tested in this run
Moving an existing WSL distro to D:	Not tested

Related pages

• First 10 minutes on a new Windows 11 PC — updates, drivers and BitLocker before development.
• Clean install Windows 11 26H2 — the base image used for this lab.
• Windows on Arm — WSL2 on Arm is a different architecture path.

Sources

• Microsoft Learn — Set up a Dev Drive on Windows 11learn.microsoft.com
• Microsoft Learn — Basic commands for WSLlearn.microsoft.com
• Microsoft Learn — Install WSLlearn.microsoft.com
• Ubuntu — WSL 24.04 rootfs imagecloud-images.ubuntu.com
• Microsoft — WSL releasesgithub.com