Case Study Pack: Teams Replacing Microsoft 365 — Outcomes, Risks, and Savings

Cutting license bills without breaking workflows: a case study pack for IT leaders

If your procurement queue and monthly SaaS bills look like a small country's GDP, you're not alone. Technology teams in 2026 face three converging pressures: rising subscription costs, tool sprawl that drags on productivity, and new privacy/compliance requirements. This compilation of real-world case studies—one of them a migration to LibreOffice—shows what IT teams achieved, where they stumbled, and how they measured cost savings, productivity impacts, and integration challenges when replacing parts or all of Microsoft 365.

Executive summary — what matters now (fast takeaways)

• Average first-year savings ranged from 20% to 65% depending on scope: removing licensed desktop Office seats yields the largest one-time reduction; full-suite replacements require more migration work but show steady savings.
• Productivity impact is rarely binary. Expect an initial 10–25% dip in collaborative workflows during a 3–8 week transition window, then recovery and often net gains when integrations are simplified.
• Top integration risks: macros/VBA, eDiscovery/archiving, single sign-on (SSO) and identity mapping, and Teams-dependent workflows (chat, apps, Planner).
• Mitigations that worked: hybrid coexistence (keep Office for macro-heavy users), Nextcloud/Collabora or OnlyOffice as cloud editing layers, staged pilots, automated batch conversions using LibreOffice headless mode, and documented rollback plans.
• 2026 trends to plan for: AI assistants in productivity tools (Copilot and competitors) are growing but also causing vendor lock-in; privacy and sovereign cloud requirements are increasing public-sector LibreOffice adoption; and automation-first migrations are now common using headless conversion tools.

Case studies — anonymized, practical, and prescriptive

Case Study A — Regional non-profit: Full desktop suite replacement to LibreOffice

Scale: 230 users. Goal: eliminate recurring desktop Office licenses; improve document privacy; stay within strict budget constraints. Timeline: 6 months (discovery, pilot, rollout).

What they replaced

• Microsoft 365 desktop licenses (Office apps)
• A small set of shared Exchange mailboxes they retained in-place (no mail migration)

Approach

1. Inventory: automated audit identified 42 users with macros and 18 with heavy PowerPoint use.
2. Pilot: 30 users across functions (programs, finance, communications) ran LibreOffice for 8 weeks.
3. Hybrid strategy: retained 15 legacy Office licenses in a floating pool for macro or advanced layout tasks.
4. Cloud editing: deployed Nextcloud + Collabora Online to provide browser-based co-editing and centralized storage—addressing one major LibreOffice gap (native cloud co-editing).
5. Training: two 90-minute role-based workshops and short job-aid videos for common tasks. For quick, low-cost training video kits and microlearning production consider lightweight field gear reviews such as the Budget Vlogging Kit.

Outcomes (real numbers)

• Annual licensing savings: $31,200 (example calculation: 230 users × $12/month previously paid × 12 months; they renegotiated a narrow set of retained licenses).
• Productivity: 3-week productivity dip in shared document co-authoring; 95% of users reported no long-term loss after 2 months; heavy macro users (6%) required the floating Office pool.
• Support load: first 90 days saw a 40% increase in helpdesk tickets on document formatting; those tickets dropped by 85% after targeted training and two automated conversion rounds.

Key technical wins and adjustments

• Batch conversion of legacy .docx/.xlsx to ODF where appropriate using LibreOffice headless mode (example below).
• Integrity checks for tables/complex layout; the design team retained Office for slide master fidelity.
• Used a small Windows VM with Office installed to render PDFs from complex templates as part of a scheduled job.

soffice --headless --convert-to odt --outdir /mnt/converted /data/*.docx
# Loop for nested folders (bash)
find /data -name '*.docx' -print0 | xargs -0 -n1 -P4 soffice --headless --convert-to odt --outdir /mnt/converted

Case Study B — Mid-size engineering firm: Split replacement (Teams → Slack, OneDrive/SharePoint → Google Drive)

Scale: 1,150 users. Goal: reduce overlapping collaboration licenses and standardize on developer-friendly tools. Timeline: 10 months.

What they replaced

• Microsoft Teams for internal chat and light collaboration
• SharePoint/OneDrive largely replaced by Google Drive for team folders and Docs

Approach

1. Business mapping: mapped 120 Teams-required integrations (CI hooks, bots, Planner use).
2. API parity: rebuilt 14 bots used in incident response as Slack apps; shifted CI notifications to Slack and GitHub Actions.
3. Data migration: used a phased export/import approach for SharePoint to Google Drive with metadata preserved where possible.
4. eDiscovery & compliance: retained a read-only archive of Exchange and SharePoint for legal hold (hosted on an archive appliance) to avoid risk. See guidance on how to audit and preserve legal tech archives.

Outcomes

• First-year TCO reduction: ~38% when combining license reductions and efficiency gains in CI and repo management.
• Integration pain: two-month delay due to an overlooked Planner-to-Jira connector that supported release triage; resolved by building a lightweight sync service using patterns from integration blueprints such as integration blueprints.
• Productivity: engineering teams reported faster incident triage with Slack + GitHub; business stakeholders missed some SharePoint features (pages and structured lists).

Case Study C — Public-sector agency: Phased LibreOffice adoption with sovereign cloud constraints

Scale: 4,200 users across offices with data residency rules. Goal: reduce vendor lock-in, comply with national data sovereignty rules, and lower costs. Timeline: 18 months (phased by department).

Approach & constraints

• Procurement required open-source or on-prem solutions where possible.
• Deployed LibreOffice on hardened workstations; used Collabora Online hosted on a government-approved cloud for co-editing, paying special attention to edge and sovereign deployment patterns.
• Implemented strict change-control for macros: automated detection of Office macros in legacy documents and a policy to rewrite critical macros into server-side services.

Outcomes

• Budget impact: license budget reduced by 57% in year one after eliminating most desktop seats and negotiating limited concurrent-seat access for advanced users.
• Risk: 7% of legacy templates required redesign due to macro reliance; mitigated with developer time to reimplement functions as internal APIs.
• Compliance: improved audit posture because local file storage and sovereign cloud provided clear data residency evidence.

"We chose a hybrid model: LibreOffice for the majority, and a small pool of managed Office seats for legacy macros. That combination reduced cost and gave us an upgrade path for problematic workflows." — CIO, anonymized public agency

Quantifying savings and productivity — how to build your model

Every migration has three categories of cost and benefit: direct license changes, migration/engineering costs, and ongoing support costs. Here is a repeatable, conservative model to estimate first-year impact.

Simple TCO formula (first year)

// Annual savings = users * (old_monthly - new_monthly) * 12 - migration_costs
function annualSavings(users, oldMonthly, newMonthly, migrationCosts) {
  return users * (oldMonthly - newMonthly) * 12 - migrationCosts;
}

Use ranges for oldMonthly and newMonthly when vendor pricing is uncertain. Include floating pools or retained licenses as a separate cost line.

Include hidden costs

• Training and productivity dips — estimate 0.5–2 weeks of lost productivity per user in worst-case scenarios.
• Application rewrites (macros, scripts) — treat these as engineering projects with backlog prioritization.
• Archive and compliance exports — often a fixed project cost, not per-user. See examples and migration patterns for content and backup transitions at platform migration guides.

Top integration challenges and practical mitigations

1. Macros and VBA

Problem: Many mission-critical Excel, Word, and PowerPoint macros are written in VBA and won’t run natively in LibreOffice.

• Inventory macros with an automated scanner (e.g., parse files for VBA modules).
• Reimplement critical logic as server-side services (APIs) or Python scripts that run centrally.
• Maintain a floating Office pool for legacy-only workflows.

2. Co-authoring & cloud editing

Problem: LibreOffice desktop lacks native cloud co-editing comparable to Microsoft 365 or Google Docs.

• Pair LibreOffice with Nextcloud + Collabora Online or OnlyOffice to provide web co-editing (many successful govt and NGO rollouts used this pattern). For offline and local-first workflows evaluate local-first edge tools.
• For teams requiring advanced real-time co-editing and AI assistants, evaluate hybrid models instead of a full replacement.

3. eDiscovery & archiving

Problem: Legal and compliance teams rely on Exchange and SharePoint eDiscovery features.

• Archive mailboxes and SharePoint sites into a compliant archive (read-only) before migration. See how to audit and preserve archives in legal tech audit guidance.
• Ensure retained archives are searchable and accessible to legal with preserved metadata.

4. Identity, SSO, and provisioning

Problem: Mapping Azure AD identities into new services and ensuring SSO works consistently.

• Use SAML/OIDC where possible and test group claims for role-based access.
• Automate provisioning with SCIM and test provisioning for a pilot cohort. Integration patterns and blueprints such as integration blueprints help reduce surprises.

5. Teams workflows and integrations

Problem: Teams acts as a hub for apps, bots, and approvals—removing it can break processes.

• Map critical automation flows (incident, release, approvals) and rebuild minimal connectors in Slack or internal chat platforms.
• Consider bridging strategies during transition (e.g., cross-posting key messages to a retained Teams channel until parity achieved).

Practical migration checklist (for IT leaders)

1. Discovery: automated inventory of apps, macros, integrations, and Teams apps.
2. Pilot: 2–10% of users across functions for 4–8 weeks with measurable KPIs.
3. Coexistence: design floating license pools and archive strategies for rollback safety.
4. Training: role-based sessions, microlearning, and job aids for the first 90 days.
5. Automation: batch convert non-critical documents, rewrite macros as services, and automate provisioning.
6. Compliance: preserve legal hold exports and eDiscovery access before final cutover. Look to migration patterns and archive-preservation guides such as platform migration guides for approaches to large export jobs.
7. Measurement: track tickets, collaboration metrics (files edited per week), and user satisfaction.

2026 trends and why they matter to migration planning

Late 2025 and early 2026 saw two important trends that affect migration decisions:

• AI features are differentiators and lock-in vectors. Copilot-like assistants are increasingly embedded in productivity suites. That drives user preference and can make a replacement feel like a capability loss. Mitigation: provide alternative AI or automation where possible (internal LLM hooks, selective retention of premium seats for power users). See research on how guided AI learning tools change workflows and lock-in dynamics.
• Privacy & sovereign cloud policies are rising. Governments and large enterprises increasingly mandate data residency—this is a primary driver for LibreOffice + Nextcloud/Collabora adoptions in the public sector. Review edge and sovereign deployment patterns at edge migrations.
• SaaS consolidation and optimization tools are maturing. By 2026, IT teams have better discovery tools to pinpoint unused licenses and orchestration platforms to coordinate staged migrations.

Lessons learned — distilled for IT leaders

• Pilot widely, roll out slowly. A broad pilot across roles is more predictive than a long pilot with a single team.
• Keep a fallback pool of Office seats. It reduces business risk and shortens remediation time for complex templates or macros.
• Automate document conversion, but validate. Headless conversion scales, but visual validation is required for templates and layouts.
• Don’t underestimate behavioral change. Even when technical parity is high, users need clear communication and training to adopt new habits.
• Price isn't the only metric. Look at TCO, compliance overhead, and strategic control over data.

Actionable next steps (30/60/90 day plan)

First 30 days

• Run an automated inventory of Office users, macros, Teams apps, and SharePoint sites.
• Select pilot cohorts across roles (admin, finance, engineering, communications).
• Build a simple TCO model using your real subscription numbers. Consider case studies like consolidation-led savings examples.

Day 31–60

• Execute the pilot—measure baseline metrics (ticket count, time to edit, user satisfaction).
• Set up co-editing layers if using LibreOffice (Nextcloud+Collabora or OnlyOffice).
• Plan macro rewrites for critical templates.

Day 61–90

• Begin staged rollouts with training and the floating Office pool enabled.
• Validate eDiscovery and archive exports—use archive-preservation patterns from migration guides such as platform migration guides to size export jobs and storage.
• Recalculate projected savings and report to finance with a recommended go/no-go.

Final verdict — are replacements worth it?

There is no universal answer. Our case studies show that partial or full replacements of Microsoft 365 can yield substantial cost savings and improved control over data—especially for organizations with heavy compliance or budget pressures. However, the success of any migration hinges on realistic discovery, effective mitigation of macro/Teams dependency, and an honest accounting of productivity impacts during transition.

Call to action

If you’re an IT leader planning to evaluate alternatives to Microsoft 365, start with a data-driven discovery. Download our migration checklist and conversion scripts, or contact our team at diagrams.site for a tailored migration readiness review and a pilot plan that maps to your compliance and integration requirements.

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