Windows 7's native disk management allows temporary VHD mounting through Disk Management or Diskpart, but the attachment doesn't persist across reboots. This becomes problematic when you need consistent drive letters for development environments, testing configurations, or automated scripts.

While Windows 7 doesn't offer GUI options for persistent mounting, we can achieve this through several technical approaches:

1. Using diskpart Scripts

Create a batch file that executes at startup:

@echo off
echo select vdisk file="C:\path\to\your.vhd" > mount.txt
echo attach vdisk >> mount.txt
echo select partition 1 >> mount.txt
echo assign letter=X >> mount.txt
diskpart /s mount.txt
del mount.txt

2. Registry-based Auto-mount

Modify the registry to enable automatic mounting:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\FsDepends\Parameters]
"VirtualDiskExpandOnMount"=dword:00000004

For more control, use PowerShell scripts with Task Scheduler:

# Save as MountVHD.ps1
$vhdPath = "C:\VHDs\development.vhd"
Mount-VHD -Path $vhdPath -Persistent
Get-VHD -Path $vhdPath | Get-Disk | Get-Partition | Add-PartitionAccessPath -AccessPath "X:"

• Ensure VHD isn't marked as read-only
• Verify sufficient privileges for mounting operations
• Check for drive letter conflicts
• Confirm VHD file integrity with CHKDSK

Tools like ImDisk Toolkit or OSFMount provide GUI options for persistent mounting and additional features like RAM disk creation.

Many Windows 7 administrators and developers need persistent virtual hard disk (VHD) attachments for scenarios like:

• Maintaining portable development environments
• Running automated tests against fixed disk images
• Storing application data in isolated containers

Here are three reliable methods to achieve permanent VHD mounting:

Create a diskpart script (mount_vhd.txt):

select vdisk file="C:\path\to\your.vhd"
attach vdisk
assign letter=Z

Then create a scheduled task with these settings:

schtasks /create /tn "Mount VHD" /tr "diskpart /s C:\scripts\mount_vhd.txt" /sc onstart /ru SYSTEM

Add the VHD path to the HKLM\SYSTEM\CurrentControlSet\Services\FsDepends\Parameters key:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\FsDepends\Parameters]
"VirtualDiskPaths"=hex(7):43,00,3a,00,5c,00,76,00,68,00,64,00,5c,00,64,00,65,\
00,76,00,2e,00,76,00,68,00,64,00,00,00,00,00

Create a mount_vhd.bat file with elevated privileges:

@echo off
echo select vdisk file="C:\vhd\dev.vhd" > %temp%\vhd_script.txt
echo attach vdisk >> %temp%\vhd_script.txt  
echo assign letter=Z >> %temp%\vhd_script.txt
diskpart /s %temp%\vhd_script.txt
del %temp%\vhd_script.txt

Check attachment status using:

diskpart
list disk
list volume

Common issues and solutions:

• If the VHD fails to attach, ensure the path is correct and accessible early in boot
• For UAC-related problems, run scripts with elevated privileges via Task Scheduler
• Check Event Viewer for disk-related errors under System logs

For a more robust solution in PowerShell:

$vhdPath = "C:\VHDs\Development.vhd"
$driveLetter = "Z"

$script = @"
select vdisk file="$vhdPath"
attach vdisk
assign letter=$driveLetter
"@

$script | Out-File -FilePath $env:TEMP\vhd_attach.txt -Encoding ASCII
Start-Process -FilePath "diskpart.exe" -ArgumentList "/s $env:TEMP\vhd_attach.txt" -Wait
Remove-Item -Path "$env:TEMP\vhd_attach.txt" -Force