Expanding an FSLogix profile disk

See this article for general information on FSLogix: What MSPs Need to Know About FSLogix Profile Containers


With a recent update to FSLogix (v2105 https://docs.microsoft.com/en-us/fslogix/whats-new) you can now update existing VHD(x) container size limits by editing the registry on your template/hosts.  This change can be made by editing the SizeInMBs value in the FSLogix registry under: HKLM\SOFTWARE\FSLogix\Profiles



This change can be made directly on your templates, hosts or deployed via GPO with a registry edit after updating to FSLogix v2105 or above on your template/hosts.  



By default, FSLogix sets the maximum profile disk size at 30GB. Note that this is not a Nerdio configuration, it is simply the default setting for the FSLogix service that Microsoft has incorporated into AVD. While 30GB is more than sufficient for most users, there are occasions where expanding the disk may be necessary. Before starting, make sure that the user is completely logged off so that the disk file will not be locked. Note that this process does not expand the existing disk, it creates a new profile disk and mirrors data from the original.

You will need to log into a session host with an administrator account to proceed. The IP address of the session host can be found by clicking on "Manage Hosts" from the servers blade in the Nerdio admin portal. To connect to the session host, you will first need to connect to DC01, then use RDP to connect to the host. For directions on connecting to DC01, see our video guide:

Accelerate - Connect to DC01 via RDP – Nerdio Help Center

Once connected to the session host, use the following steps:

1. To use the FRX.exe tool, open a command prompt and change the working directory to the FSLogix Apps folder:

 cd "C:\Program Files\FSLogix\Apps"

2. Obtain the file path for the profile disk you would like to resize. Profile disks are stored under


For example, Andy ITAdmin's disk would be at the following location:


To save some time, rename the existing disk file so that the command can be used to create a file with the original name. For this example, we have changed the file name to oldProfile_AITAdmin.vhdx.

3. Copy the file path and use it in the migrate-vhd command to create a new disk in the same profile directory. In this example, we will use the Andy ITAdmin account, and the new disk will have a size of 40GB:

frx.exe migrate-vhd -src \\fs01\e$\PROFILES\AITAdmin\SID_AITAdmin\oldProfile_AITAdmin.vhdx -dest \\fs01\e$\PROFILES\AITAdmin\SID_AITAdmin\Profile_AITAdmin.vhdx -size-mbs=40960 -dynamic=1

4. A new disk will be created and data will be mirrored from the old profile disk. This may take some time to complete. Note that you may receive the following error message:

  Error mirroring files (0x0000001D): The system cannot write to the specified device.

This is due to some Microsoft Edge files under the user's AppData folder and can be safely ignored.

5. Grant the user full control to the new VHDX file.

6. Check Computer Management on FS01 and close any open files pertaining to the user's profile.

7. Have the user sign in to verify access to their profile.

At this point, the old user profile disk still exists. It can be deleted to free up space once the user can confirm their profile is working correctly.


For more information on FSLogix container default settings and configurations, see the Microsoft documentation article: Profile Container registry configuration settings - FSLogix | Microsoft Docs

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