Senior Application Packager - MSIX Specialist - inside IR35
Senior Application Packager - MSIX Specialist - inside IR35 - £450 to £550 per day - hybrid working (minimum of 2 to 3 days on site per week in Warickshire, non-negotiable)
Brief overview:
We are looking for a highly experienced,technically accomplished Application Packager with a strong emphasis on MSIX — someone who understands not only how to build MSIX packages, but also its architectural constraints, containerisation model, staging/registering behaviour, service limitations, App Attach implications, and how these affect real-world enterprise delivery.
You will be working across a large-scale, complex estate dominated by non-persistent Citrix VDI, with a smaller but business-critical Intune-managed laptop estate, delivering high-quality, supportable packages into production.
This is not a generalist EUC role, you will be a time-served application packaging specialist with a strong recent focus on MSIX.
Key Requirements
We need someone who can demonstrate deep, practical MSIX expertise, including:
- Expert-level understanding of MSIX architecture, including staging vs registration, container isolation, VFS, private registry hives, user-context behaviour, and package signing.
- Strong knowledge of MSIX limitations, particularly around services, drivers, global COM, system-level integrations, and constraints of per-user registration.
- Hands-on experience with MSIX Packaging Tool and third-party tooling (e.g. TMEditX), conversion workflows, package editing, manifest troubleshooting, PSF (Package Support Framework), and fixups.
- Experience deploying MSIX in enterprise environments using AppVentix and/or App Attach.
- Ability to advise on MSIX suitability assessments, edge-case remediation, and – importantly - when not to choose MSIX and retain current App-V 5.x packages.
- Confidence working with MSIX in non-persistent VDI.
Other Core Packaging Skills
We are looking for deep, battle-tested experience across traditional and modern packaging technologies:
- App-V 5.x: Sequencing, dynamic configs, connection groups, troubleshooting and advanced isolation behaviour.
- MSI:
- Strong understanding of MSI tables, transforms, property management, and component rules.
- Ability to perform table-level edits and build complex packages from scratch.
- Experience authoring Custom Actions and handling major/minor upgrades.
- PSADT (PowerShell App Deployment Toolkit):
- Building enterprise-grade scripted installers
- Complex logic branching, pre-req checks, remediation, logging, rollback.
Enterprise Management & Deployment Tools
- Packaging and deployment via MECM (SCCM) (Application Model & Packages).
- Intune application model experience (Win32, MSIX, dependency chains, detection rules).
- Practical knowledge of AppVentiX for App-V/MSIX delivery and VDI publishing.
- Awareness of FSLogix, profile containers, App Masking and their interplay with MSIX/App-V.
Environment & Infrastructure Knowledge
- Proven experience supporting application delivery in large, complex enterprises with strict governance.
- Understanding of app delivery to Citrix non-persistent VDI, image management, profile volatility, and session behaviour.
- Understanding of packaging for physical laptops (Intune-managed), including conditional access, offline use, and device-based policies.
- Ability to troubleshoot across the entire application stack: OS integrations, dependencies, runtimes, COM, registry, file system, permissions, and virtualisation layers.
Soft Skills & Delivery Expectations
- Able to work autonomously in a high-pressure environment with shifting priorities.
- Can produce high-quality technical documentation, handover notes, and packaging standards.
- Capable of engaging with developers, infra teams, security, and support to resolve complex issues.
- Strong investigative mindset — able to deep-dive into logs, manifests, event traces, ProcMon captures, and debug difficult packaging failures.
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