.doc, .xls, and .ppt files sitting in archived SharePoint document libraries and migrated OneDrive folders have long been a blind spot for automated cloud compliance at scale.
Microsoft is now working to close that gap. According to Microsoft 365 Roadmap entry 574363, published on October 13, 2026, Microsoft Purview Information Protection is adding server-side auto-labeling support for legacy Microsoft Office file formats—specifically Word (.doc), Excel (.xls), and PowerPoint (.ppt). Currently listed as in development for Worldwide (Standard Multi-Tenant) cloud instances, both Preview and General Availability are targeted for November 2026.
Closing the Format Gap in SharePoint and OneDrive
To appreciate why this matters, it helps to look at how Microsoft Purview handles sensitivity labels today. According to Microsoft Learn documentation on automatic sensitivity labeling, Purview divides auto-labeling into two distinct mechanisms: client-side labeling (which occurs inside Word, Excel, PowerPoint, and Outlook as users actively edit files or compose emails) and service-side auto-labeling.
Service-side auto-labeling runs directly in the cloud backend to evaluate and classify data at rest in SharePoint and OneDrive (as well as data in transit in Exchange). Because service-side policies operate independently of whatever Office client version a user has installed—and without requiring a human to accept or dismiss a prompt—they are the primary tool for enforcing organization-wide compliance at scale.
Until now, however, Microsoft Learn's documented list of supported file types for SharePoint and OneDrive service-side auto-labeling has been strictly limited to PDF documents and modern Open XML formats: .docx, .pptx, and .xlsx. While SharePoint and OneDrive could recognize and display an existing label on an uploaded .doc or .xls file, the service-side auto-labeling engine itself could not inspect and apply sensitivity labels to those legacy formats at rest. If an organization migrated terabytes of historical file shares into SharePoint Online, admins either had to bulk-convert legacy files to modern Open XML formats or rely on manual and client-side workflows to get them labeled.
If delivered as outlined in Roadmap ID 574363, Purview's server-side engine will be able to automatically evaluate and apply sensitivity labels to .doc, .xls, and .ppt files stored in SharePoint and OneDrive.
Section Summary:
- Roadmap ID: 574363 (Published October 13, 2026).
- Scope: Server-side auto-labeling in SharePoint and OneDrive for legacy Word (
.doc), Excel (.xls), and PowerPoint (.ppt) files. - Target Release: Preview and General Availability estimated for November 2026 (Worldwide Standard Multi-Tenant).
Current Operational Boundaries and Prerequisites
While the roadmap entry gives a brief summary of what is coming, Microsoft's existing Purview documentation establishes the technical rules of the road for service-side auto-labeling. Administrators planning to take advantage of legacy file support should keep the current service architecture in mind—while noting that Microsoft has not yet published whether legacy binary formats will carry any format-specific caveats or require separate tenant toggles when the feature rolls out.
| Feature / Boundary | Current Documented Service-Side Behavior | Legacy Format Impact (.doc, .xls, .ppt) |
|---|---|---|
| Supported Formats Today | .docx, .xlsx, .pptx, and .pdf (PDF requires explicit tenant enablement) | Currently unsupported; fails with FileNotSupported or FileExtensionNotSupported |
| Planned Roadmap Scope | N/A | Server-side evaluation and labeling in SharePoint and OneDrive (Est. Nov 2026) |
| File State Requirements | Files must be at rest; open or checked-out files are skipped until closed/checked in | Expected to follow standard SharePoint/OneDrive lock and session rules |
| Licensing Tier | Requires Microsoft 365 E5 or equivalent P2-tier compliance add-on (not included in E3 or Business Premium) | Standard Purview auto-labeling licensing applies |
| Simulation Requirement | Policies save in simulation mode by default before production enforcement | Essential for testing how legacy files match sensitive info types before applying labels |
Under current Microsoft Learn guidelines for SharePoint and OneDrive auto-labeling, several operational prerequisites and limits apply:
- Tenant Enablement: Sensitivity labels must be enabled for Office files in SharePoint and OneDrive (configured via the Microsoft Purview portal or the
Set-SPOTenantPowerShell cmdlet), and Microsoft 365 auditing must be turned on. - Open Sessions and Checked-Out Files: Service-side auto-labeling cannot modify a file while it is open in an active user session or checked out in a SharePoint library.
- Sensitive Information Type (SIT) Timestamps: By default, auto-labeling evaluates content created or modified after a given Sensitive Information Type was created or updated. As Microsoft Learn notes, classifying older, unchanged files against a newly created SIT requires running on-demand classification first and waiting for the next policy pass.
- Search Index Dependencies: Re-evaluation in SharePoint and OneDrive depends on the search index picking up changes, which can take several days across large tenants (100+ sites) following bulk updates or re-indexing.
- Encryption and Password Boundaries: SharePoint and OneDrive cannot read or apply sensitivity labels to password-protected documents or files protected with external/non-Microsoft encryption (which trigger the
EncryptedFileNotSupportedfailure code). Additionally, service-side processing does not apply to files encrypted with Double Key Encryption (DKE) or on-premises keys ("hold your own key" / HYOK), and labels that apply encryption to SharePoint and OneDrive locations must be configured with Assign permissions now and User access to content expires set to Never.
How Admins Can Prepare Before November 2026
Because Roadmap ID 574363 is still in development, .doc, .xls, and .ppt files are not yet eligible for automatic server-side labeling. If an active policy encounters them today, the operation simply leaves the file unchanged and logs a format failure. However, compliance teams can take practical steps right now to prepare their tenants:
- Audit Current Labeling Failures: Sign in to the Microsoft Purview portal with a Compliance Administrator, Compliance Data Administrator, Information Protection Admin, or Information Protection Analyst role. Navigate to Information Protection > Auto-labeling (or Solutions > Information Protection > Policies > Auto-labeling policies in the newer portal experience), select an active policy, and check the Labeling failures tab. Reviewing items flagged with
FileNotSupportedorFileExtensionNotSupportedwill give you an immediate inventory of where legacy Office files are sitting in your scoped SharePoint sites. - Watch for Rule-Matching Quirks: If your auto-labeling rules rely on the
Document property iscondition mapped to a SharePoint managed property (such asRefinableString11), Microsoft Learn warns that values containing an ampersand (&)—for example,Billing & payment document—might fail to match. Clean up metadata strings ahead of time. - Use Simulation Mode First: Never flip a new or expanded auto-labeling policy straight into production enforcement. Because service-side policies apply labels silently without user confirmation, always run your policy in Simulation mode first. Use the Items to review tab (requires the Data Classification Content Viewer role to preview file contents) to verify that your Sensitive Information Types aren't triggering false positives across decades-old spreadsheets and Word documents.
Section Summary:
- Check the Labeling failures tab in the Purview portal to see how many legacy files are currently being skipped by your policies.
- Ensure tenant prerequisites—such as SharePoint/OneDrive sensitivity label integration and M365 auditing—are active.
- Plan to use Simulation mode and on-demand classification once the feature hits Preview in November 2026 to safely catch up on historical file shares.