MSIX App Attach and FlexApp – Better Together


Now that Azure WVD is GA, you are starting to hear more about MSIX and the strategy of attaching applications to a WVD OS. MSIX is the Windows app package format that provides a modern packaging experience to all Windows apps. The MSIX package format preserves the functionality of existing app packages and/or install files in addition to enabling new, modern packaging and deployment features to Win32, WPF, and WinForm apps.

Since host pools in WVD are multi-user, the user could login to different hosts any given login. So, no matter how your host pools are setup; like a temporary Persistent OS and/or by using Ephemeral OS Disks, you will have the challenge of persisting applications between sessions which would usually necessitate tedious base image management due to ongoing application installations and updates.

Ideally, you want the freedom of being able to re-image the OS at any time, without worrying about what is physically installed into the OS. To achieve this, you need to decouple applications from the OS. Providing a layer of application abstraction from the base OS allows applications to be snapped in on the fly. This is something we at Liquidware have been perfecting for many years now and are excited to see ALL the big desktop players embrace, including VMware (App Volumes), Citrix (App Layering with UniDesk) and soon with the forthcoming Microsoft (MSIX with App Attach).

First let’s talk to MSIX. As described before, MSIX is the new, modern app packaging method for both ISVs and IT professionals. MSIX itself is based on App-V’s core technology.   I like to call it App-V lite. So yes, it will have some limitations out-of-the box because of isolation. Application isolation causes challenges with complex applications and apps with drivers and services which have an impact on packaging and deployment success rates.  Applications need to be compiled natively in the emerging MSIX format or the app may need to undergo a process to convert non-MSIX installers.  Microsoft provides an MSIX packaging tool for this.

So, what problem does MSIX App Attach solve? When you register an MSIX package to Windows, it follows the Windows modern application path. It extracts itself to the local hard drive of the OS. This process is like extracting a ZIP file over the network, which can take some time. The goal of MSIX App Attach is to pre-cache this process on a VHD, and then attach the VHD to the OS before the MSIX gets registered. Once the registration process starts it’s quick, as Windows thinks the application is already extracted to the OS because of the VHD cache.

While some applications will be ideal candidates for MSIX App Attach, many others will not. This may be for a number of reasons, including challenges in the attempted conversion to MSIX or because of isolation, which may impede an app’s ability to function seamlessly. For this reason, Liquidware has partnered with Microsoft to complement MSIX App Attach with our FlexApp solution. Here are the strengths of using FlexApp with application delivery technologies from Microsoft:

  • FlexApp has been found to have the highest application compatibility known in the industry – ~90% or greater.
  • Seamless compatibility with complex applications, including those with drivers and services dependencies.
  • Zero app isolation – FlexApp attached applications are not isolated and therefore have native interaction capabilities with Windows and other applications.
  • FlexApps work across any supported Windows OS with no need to repackage applications.
  • FlexApps are flexible and can be attached at boot, login, with Click-to-Layer™, or by context-aware filter.
  • FlexApp micro isolation – simplifies the packaging of apps through automatic resolution of individual potential file conflicts.
  • FastPackaging™ technology – enabling applications to easily be packaged in the same time it takes to install the application one-time.

Our current available version and functionality with Microsoft WVD is impressive (see video demo) but next quarter you can expect even further leading features from FlexApp including:

  • (Q1 2021) Single Pane of Glass: ProfileUnity can manage applications installed in the base image, MSIX, and App-V packages in the UEM side of the product. ProfileUnity is integrated with FlexApp when fully licensed, enabling the solution to manage all applications through a single interface, including MSIX, App-V and FlexApp packages.
  • Q1 (2021) We can cloak away on a per user basis any applications in the base image. These applications tend to not update often or can’t be delivered with MSIX or FlexApp. For this scenario, we can help reduce image sprawl that’s caused by building out images based on department specific applications. We can cloak unnecessary applications away from the user. This approach helps to combine more apps into a single base image, but still restricts access.
  • (Q1 2021) Extending MSIX and App-V delivery options: Our context aware filtering system can make over 200+ decisions regarding when it delivers an MSIX and App-v package to a user or when it doesn’t. Admins can choose to deliver MSIX and App-V packages to the OS at boot or during the login. As a side note, ProfileUnity NEVER holds off the user login to register MSIX, App-V or FlexApp layers to the OS; this process is done in parallel to the login routine.
  • (Q2 2020) IT packaged MSIX packages or direct from ISV MSIX packages can be directly converted to a FlexApp, which gains you a lot more flexibility in delivery options.

Picking up where MSIX ends: If you decide to try deploying applications using MSIX packages first and the success rate and delivery options are less then desirable; FlexApp can pick up where MSIX leaves off. You have a few options.

  • (Q1 2021) Cloak away base image installed applications.
  • (Q1 2021) Manage the MSIX package in its native format with ProfileUnity.
  • (Q2 2020) Convert the MSIX package into a FlexApp layer directly.
  • Recapture the application install directly into a FlexApp layer.



We welcome you to try FlexApp in your environment — on prem, VMware, Citrix or Azure WVD. You can go to the Azure Marketplace or our download page to get started.

One thought on “MSIX App Attach and FlexApp – Better Together

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