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. PLEASE NOTE: This role is inside IR35 and requires candidates to be onsite in Warwickshire 2 to 3 days per week.