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FSLogix Anatomy + Common Issues: Storage, App, Profile Container 

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Here at Nerdio, we’ve been entrenched in Azure Virtual Desktop (AVD) since the very beginning, which means we’re chock-full of knowledge about Microsoft’s recommended profile solution for AVD: FSLogix.   

FSLogix may be new to many MSPs who haven’t worked with Azure or AVD, so we’re always compiling tips and helpful ways to train MSPs on what FSLogix is and how to troubleshoot it.  The best route for training we’ve found with FSLogix is to start with breaking down its anatomy and the related common troubleshooting issues for each component.  

For those seeking a deeper understanding of FSLogix and its impact on virtual desktop environments, this blog post serves as an essential resource. In this comprehensive guide, we will explore the intricacies of FSLogix and shed light on its crucial role in addressing common challenges associated with storage, application management, and profile containers. As MSPs and IT professionals navigate the complexities of virtual desktop infrastructure, gaining insight into FSLogix’s functionality and its potential solutions to prevalent issues becomes paramount. By examining its anatomy and delving into practical strategies, this article empowers readers with the knowledge needed to harness the full potential of FSLogix, enhance performance, and streamline user experiences.

What is FSLogix? 

FSLogix is a robust profile solution for non-persistent desktops (like AVD hosts). It is Microsoft’s recommended profile solution for AVD and moves MSPs away from “roaming” profiles to a profile that is mounted and feels like a local profile.   If you’ve worked with User Profile Disks (UPDs), you’ll feel right at home with FSLogix. 

3 Moving Parts 

FSLogix’s name may be more intimidating than what is really under the hood. There are essentially three pieces at its core.  


Most users decide to use one of two FSLogix storage options: either a file server VM (virtual machine) or Azure Files. A file server VM requires the user to manage the underlying server object, and it needs to be in the same region as the host. Azure Files uses Azure Storage, which is an IaaS (Infrastructure-as-a-Service) service, so the underlying assets don’t need to be manually managed. Using premium storage is recommended for both a file server VM and Azure Files. Learn more about these options in this video.  

You’ll find when adding an account in Nerdio Manager for MSP that you are required to establish a new, or pointing to an existing, FSLogix storage path.  This Server Message Block (SMB) share is where the FSLogix profile containers will be stored.  Permissions are critical to this share and are the most common support request we see with FSLogix.  You can find more information about FSLogix permissions via  Microsoft’s documentation linked HERE

The performance of your storage is a major player in FSLogix performance. Slow login times are a common symptom of under-performing storage. If Azure Files is used for this storage, we always recommend using premium storage and perhaps auto-scaling your Azure Files storage to optimize through put during working hours.  Nerdio Manager for MSP has a great feature for Auto-Scaling Azure Files. This scaling feature can also ensure there is adequate available space as your FSLogix storage grows.  One last word of caution on the storage front – you must back up your FSLogix storage! It is essential as it stores user profile data. 

FSLogix Application 

The second piece of the FSLogix puzzle is the application. We rarely see a support issue related to the FSLogix application itself and more often we’ll see a misconfiguration of the FSLogix settings. The FSLogix app is only required on a session host (AVD host) that users are logging into. It is not required on the user’s storage device, image or anywhere else they would not be logging in.   

The biggest things we see MSPs struggle with related to the application are updating the registry settings and keeping the application updated to the latest version.  

Registry settings for the FSLogix application are used to provide FSLogix settings and point FSLogix to your storage location.  Nerdio Manager for MSP allows you to store these settings in an FSLogix Configuration profile under Settings>Integrations for your customer accounts.   

Nerdio can then install FSLogix (latest GA version) with your settings upon AVD host creation, taking the worry out of keeping FSLogix updated and retaining your settings via our automation.  Combine this with Auto-healing features available for Auto-scale (Including FSLogix health checks) and the application piece of FSLogix is no sweat.   

Profile Container 

Yes, this is all leading up to the user profile, I promise!  With storage established and FSLogix running on the AVD host, all you need now is users.    

Upon a user’s first login, a profile container will be created in the storage location designated.   The user’s profile will be a VHDX or VHD file depending on the settings configured (with VHDX being preferred).  By default, this will include the user’s entire profile.  Think of everything that would be in a user’s C:\User\<username> folder and this will be stored in their FSLogix profile container.   

 When a user logs in, the FSLogix app will go to the storage location and mount that user’s profile container to the AVD host.  When the user logs off, this is dismounted from that host.  This gives a user the ability to potentially login to a new host with each login but feel as though they’re logging into their same desktop each day. This also gives the opportunity to scale-in (remove) AVD hosts, reimage, delete and move users to a different pool without losing their data and settings.   

Common support issues we’ll see related to profile containers include the following: 

  • Profile locked due to the file being in use 
  • Profile (VHD/VHDX) reached FSLogix’s default 30GB maximum size 
  • Symptoms are “full disk” errors, unable to receive new mail in Outlook 
  • FSLogix has a 30GB default size limit for containers. This can be expanded via registry setting 
  • Profile Corruption 
  • If the VHD/VHDX file were to be corrupted, FSLogix may rename the file with a “CORRUPT” in the file name.   
  • May be resolved by restoring a backup of the VHD/VHDX from a known working date 

FSLogix is a great solution to use alongside Azure Virtual Desktop, but it can be a complex tool. Here at Nerdio, we can help you learn how to use it. Read our blog on ‘5 Things MSPs Must Know about FSLogix for additional insights or contact us to discuss your MSP’s unique needs.

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