Purview Retention Auto-Archive for SharePoint

Microsoft Purview Data Lifecycle Management is adding an archive option to retention policies. Admins will be able to move inactive SharePoint and OneDrive files into Microsoft 365 Archive automatically, rather than archiving whole sites by hand.

The timing has moved. The original Message Center post, MC1325441, planned a rollout from mid-August to late September 2026. Microsoft updated it on 25 August 2026: public preview now runs from early September to early October 2026, and general availability runs from early October to early November 2026. If you were expecting the feature in every tenant by mid-September, plan around the later dates.

For most SMEs the benefit is simple. Old project files stop counting against your paid SharePoint storage and stop turning up in Copilot answers, but they stay available for compliance and eDiscovery.

Quick answer

1. Treat the feature as preview until your tenant shows general availability, and do not rely on it for a storage deadline.
2. Check whether you actually exceed your SharePoint storage quota. If not, archiving may not save money.
3. Set up Microsoft 365 Archive billing through a pay-as-you-go subscription before you test.
4. Pilot on one or two sites with clearly dormant content and a named business owner.
5. Confirm eDiscovery, restore and user experience before you widen the scope.

What the archive action does

According to Microsoft's announcements, the feature adds a new Archive option inside retention policy settings. Files that match the policy's inactivity condition move to Microsoft 365 Archive, which Microsoft describes as a low-cost storage tier.

Three behaviours matter for planning:

• Archived files remain discoverable for compliance scenarios such as eDiscovery.
• Archived content is excluded from Copilot indexing, which Microsoft says can improve answer relevance.
• The feature is not enabled by default. Existing retention policies do not change unless an admin edits them.

That last point is useful. Nothing happens to your files on the rollout date. You decide which locations, and which inactivity thresholds, are in scope.

What Microsoft 365 Archive costs

Microsoft Learn is clear that Microsoft 365 Archive charges for storage at a per-GB monthly rate, but only when archived storage plus active SharePoint storage exceeds the tenant's licensed storage capacity. If your tenant is under quota, archived files add no extra storage cost.

Microsoft's billing examples use a rate of $0.05 per GB per month for archived data above the quota. Check the current pay-as-you-go pricing page before you budget, as rates can change.

Other points from the pricing page:

• The reactivation fee for archived SharePoint content was removed on 31 March 2025. Reactivated content cannot be re-archived for four months.
• That change does not apply to OneDrive accounts. Unlicensed OneDrive archive storage and reactivation are billed per GB.
• If archive billing is turned off or unhealthy, archived content stays archived but counts as active storage, and new archive actions are blocked.

For an SME, the practical question is whether you are paying for extra storage today. If you are not, the main gains are less Copilot clutter and a cleaner search experience, not a lower bill.

Choosing what to archive

Good candidates are content that is finished, rarely opened and still needs to be kept:

• Closed project and client sites.
• Old marketing and event material.
• Former staff OneDrive content that is held for a retention period.

Poor candidates are anything with live links from other systems, finance records that auditors might ask for at short notice, and shared templates. Archive is not deletion, but retrieval is slower than opening a file, so users will notice.

Keep the scope small enough that one person can explain it. If your information is not yet labelled or classified, the sensitivity labels practical start guide covers how to get basic structure in place first.

How to pilot it safely

A sensible pilot runs over four to six weeks:

1. Baseline. Record current tenant storage, the storage used by the pilot sites and any extra storage packs you pay for.
2. Billing. Turn on Microsoft 365 Archive and link its pay-as-you-go billing. Set an Azure budget alert so a mistake shows up quickly.
3. Policy. Create a separate retention policy for the pilot sites only. Use a long inactivity period to start with, so only clearly dormant files move.
4. Test. Ask the site owner to find and restore an archived file. Run a content search in eDiscovery to confirm archived items appear. Ask Copilot a question that previously surfaced old content and see what changes.
5. Review. Compare storage and cost with the baseline. Record who approved the scope and any exceptions.

Do not stack this on top of other broad retention changes in the same month. If something unexpected happens, you want one clear cause.

Controls to check before wider rollout

Before extending the policy, check a few related settings:

• Retention conflicts. A retain policy and an archive action on the same location need to agree. Test on a site with a known retention setup.
• Oversharing. Archiving hides content from Copilot indexing, but it does not fix permissions on active content. The Copilot semantic index oversharing fix note covers that separately.
• Admin roles. Limit who can edit retention policies. An over-broad archive policy can move a lot of data quickly.
• User communication. Tell site owners what archived means, how to request a file back and how long it takes.

Once the pilot results are recorded, extend site by site rather than applying one tenant-wide policy.

Source basis

• MC1325441: Archive OneDrive and SharePoint files under retention (Message Center archive)
• MC1472601: Archive OneDrive and SharePoint files under retention policies (Message Center archive)
• Pricing model for Microsoft 365 Archive, Microsoft Learn
• Learn about retention policies and retention labels, Microsoft Learn