Auditing a legacy email archive can feel like a long, complex exercise. Years of accumulated data, unclear ownership and outdated policies often make it difficult to know where to start.
But it doesn’t have to take months.
With the right focus, most organisations can complete a high-value archive audit in one week — enough to understand scope, risk and readiness for migration or decommissioning.
Here’s a practical framework.
Day 1: define scope and objectives
Start by answering three questions:
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What archive platforms are in scope (e.g. Mimecast, Enterprise Vault, PSTs)?
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What is the goal — migration, decommissioning, or compliance review?
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What success looks like?
Clarity here prevents wasted effort later. Without it, audits tend to drift into technical deep-dives that don’t support decision-making.
Day 2: quantify data volume and structure
Understand what you’re dealing with:
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Total data volume (TBs)
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Number of mailboxes and journal sources
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PST presence and location
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Attachment types and sizes
This gives you a baseline for cost, complexity and timeline.
Day 3: assess data quality
Identify common issues:
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Duplicate messages
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Orphaned mailboxes
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Corrupt PST files
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Inconsistent folder structures
You don’t need to fix everything yet — just understand the scale of the problem.
Day 4: review retention and compliance policies
Examine:
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Current retention rules
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Legal hold requirements
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Deletion policies
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Differences between archive and live mail
This is often where the biggest risks sit — especially if policies haven’t been updated in years.
Day 5: analyse access and security controls
Check:
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Authentication methods (e.g. MFA support)
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Permission models
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Audit logging capability
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Integration with identity platforms
Legacy archives frequently sit outside modern security frameworks.
Day 6: evaluate search and eDiscovery capability
Test real-world scenarios:
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How long do searches take?
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Are results complete and consistent?
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Can Legal and IG teams rely on the output?
This step is critical for understanding operational risk.
Day 7: summarise findings and define next steps
Bring everything together into:
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A high-level data inventory
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Key risks and gaps
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Estimated migration complexity
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Recommended next actions
The goal isn’t perfection — it’s clarity.
Why a one-week audit works
A focused audit avoids over-analysis and gives stakeholders what they need:
a clear picture of cost, risk and effort.
It turns unknowns into decisions.
And in most cases, it reveals the same conclusion:
The archive isn’t just old — it’s holding the organisation back.