Azure Virtual Desktop: FSLogix VHD unable to shrink — Profile VHD compaction issue

Question

Azure Virtual Desktop: FSLogix VHD unable to shrink — Profile VHD compaction issue

AdminTai 0

Problem description

I am experiencing an issue where my FSLogix profile VHD/VHDX containers used with Azure Virtual Desktop are not shrinking or compacting as expected after use. The problem was first reported on September 18, 2026, and despite following common troubleshooting steps, the VHDs still do not shrink.

Environment

Azure Virtual Desktop environment using FSLogix profile containers in West US 3 region.

What I've already tried

I have not tried anything yet.

Current status

I am seeking guidance on further troubleshooting steps to resolve the VHD size not decreasing after compaction attempts.

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1 answer

Your answer

Answer 1

Hello @AdminTai

FSLogix doesn’t compact a profile container simply because files were deleted. It evaluates the container during user sign-out and only runs compaction when all documented conditions are met:

FSLogix 2210 (2.9.8361.52326) or later
Dynamically expanding VHD/VHDX
Container size on disk greater than 1 GB
Recoverable space at least 20% of the consumed size
VHDCompactDisk enabled; it’s enabled by default
The Optimize Drives (defragsvc) and Microsoft Storage Spaces SMP (smphost) services aren’t disabled

After completely signing out the affected user, check:

C:\ProgramData\FSLogix\Logs\Profile\Profile-yyyyMMdd.log

Search for WasCompacted, Disk was not compacted, or [ERROR:]. Also review Event Viewer > Applications and Services Logs > FSLogix > Apps for Events 57, 58, and 60-63. These entries identify whether the threshold wasn’t met, the disk is fixed-size, a required service is disabled, or compaction failed.

If either required service is disabled, set both startup types to Manual from an elevated PowerShell session:

Set-Service defragsvc -StartupType Manual

Set-Service smphost -StartupType Manual

Also verify whether ProfileType = 3 or VHDAccessMode = 1, 2, or 3 is configured. There's an ongoing limitation where differencing disks created by these configurations are often too small to meet the compaction threshold.

Please share the FSLogix version, whether the container is fixed or dynamic, the applicable configuration values, and the compaction-related log entry. The West US 3 location alone doesn’t establish a regional Azure Virtual Desktop issue.

References:

VHD Disk Compaction

Troubleshoot VHD Disk Compaction

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