Microsoft Project Online Retirement: The Definitive FAQ

Microsoft Project Online retirement is set for September 30, 2026. PMO directors and project managers have been sending us the same questions for months, and the answers are scattered across Microsoft documentation, partner blogs, and administrator forums. This post compiles every question we hear and answers each one in one place, so you can get the full picture without piecing it together from a dozen sources.

The diagram below clarifies the single most common source of confusion: which Project Online services stop versus which continue after retirement.

The key distinction: your project schedules, resource pool data, and timesheets live inside Project Online's SQL database—not in SharePoint. SharePoint project sites are SharePoint Online content and will persist. Your structured project management data will not be reachable after the cutover unless you export it before the deadline.

When Does the Microsoft Project Online Retirement Take Effect?

September 30, 2026. Microsoft published this date through the Microsoft 365 Admin Center on July 10, 2024 in message center notice MC812729. They have updated the Project Online retirement documentation multiple times since, but the date has not changed.

Key milestones in the retirement timeline:

• July 10, 2024 — Microsoft publishes MC812729, the official retirement notice
• October 2025 — New Project Online Professional and Premium subscriptions stopped being sold
• September 30, 2026 — Hard cutover; all remaining tenants lose service access simultaneously
• Post-retirement — SharePoint project sites remain; PWA, OData, ERP, and timesheet workflows do not

There is no extension and no deprecation-mode grace period that preserves full functionality. The service stops.

"Microsoft will probably extend it" is what PMO directors say when they don't want to start planning yet. Microsoft has not moved retirement dates for SaaS products once they are formally set. InfoPath, Skype for Business, SharePoint Workspace—none received extensions after their hard date was confirmed. The pattern is consistent.

What Exactly Stops Working on September 30, 2026?

More stops than most teams expect. The common mental model is "the website goes away." The reality is that several interdependent services stop simultaneously.

Project Web App (PWA) stops serving pages. If you navigate to https://[your-tenant].sharepoint.com/sites/pwa, you get a service-decommissioned error.

The OData API endpoint (/_api/ProjectData) returns 410 Gone. Every Power BI report, Excel pivot table, and custom dashboard that hits this endpoint stops refreshing the moment the service is decommissioned.

The Enterprise Resource Pool (ERP) becomes unreachable. Resource assignments, cost rates, calendar exceptions, skill metadata—all live inside Project Online's database, none of it exposed through SharePoint.

Timesheet workflows stop. Approvals in flight on September 30 will not complete. Pre-approve or archive any open timesheet periods before the cutover date, and decide how to handle billing entries that haven't been locked.

The Project Online Desktop Client's online sync stops. The desktop client itself continues to work for locally saved .mpp files, but any feature that requires a live connection to your PWA site—checking projects in or out, publishing updated schedules, syncing resource assignments—stops working.

Portfolio management views, PDPs, stage gates, and demand management are all decommissioned with the PWA interface.

What does not stop: SharePoint project sites, the Microsoft 365 tenant itself, and locally stored .mpp files. Those are not Project Online artifacts.

Is There a Read-Only Period After the Retirement Date?

Maybe—but you should not plan around it.

Microsoft's general guidance for SaaS retirements suggests that retired services may enter a read-only data access period before final deletion, historically around 90 days. Some earlier Microsoft retirements followed that pattern. Others did not. Critically, no Service Level Agreement or contractual commitment covers this window. If it materializes, it is a courtesy, not a guarantee.

Two practical conclusions follow from this:

First, do not schedule your data export to happen after September 30. If you are still trying to pull OData snapshots in October 2026, you have missed your planned window and are operating on borrowed time against a server that may or may not still be responding.

Second, treat September 1, 2026 as your practical export deadline. That leaves a full month of buffer before the official cutover and keeps you ahead of the surge of other organizations that will rush to export in the final two to three weeks of September. Server-side throttling under high concurrent load is a real risk, and the tenants exporting in August will not encounter it.

What Happens to Your Data After Project Online Retires?

The answer depends on which data you're asking about.

SharePoint project sites persist. Documents, issues lists, risk registers, meeting notes, and team sites associated with your projects are standard SharePoint Online content. The Project Online retirement does not affect them. What breaks is the integration between those sites and the Project Online scheduling engine—the "sync issues to SharePoint" feature simply stops functioning, but the SharePoint content itself remains.

Structured project scheduling data—tasks, dependencies, baselines, custom fields, resource assignments—lives entirely in Project Online's database. Microsoft does not give you direct SQL access. Your only extraction paths are the OData API and .mpp file exports, both of which stop working on the retirement date (or within the informal read-only window after it). Once those endpoints are gone, the data is gone.

Enterprise resource pool data is similarly locked inside Project Online. There is no officially supported bulk export format for the full ERP. You can pull it via OData before retirement—resources, rate tables, calendar exceptions, skill metadata—and reconstruct it in your destination system. After retirement, that data is unreachable.

Timesheet history is the item with the highest compliance exposure. If your SOX audit scope, ISO 9001 controls, or client billing processes require three years of timesheet records, you need to export that history and archive it in a format you control before the cutover. Project Online timesheet data is not synced to SharePoint, Dynamics, or any other Microsoft system automatically. If you don't export it, it disappears.

Custom fields, lookup tables, and view definitions are metadata—relatively easy to enumerate and document. The challenge is not exporting the definitions but mapping each field to the destination tool's data model. Do that mapping work before the technical export, not after.

Can You Extend a Project Online Subscription Past September 30?

No. Microsoft stopped accepting new Project Online Professional and Premium subscriptions in October 2025. Existing subscriptions continue until their current term, but no subscription can be renewed past September 30, 2026. Microsoft has been explicit about this in every customer communication since the retirement announcement.

If you are on an Enterprise Agreement or CSP arrangement with renewal language scheduled beyond that date, work with your Microsoft licensing partner to understand how the contract term intersects with the service retirement. In most interpretations, the service retirement supersedes subscription renewal language—you cannot pay Microsoft to keep Project Online running past the shutdown date.

What Is Microsoft's Recommended Path, and Does It Cover Enterprise PMOs?

Microsoft directs Project Online customers toward two products: Microsoft Planner (the unified successor that absorbed Project for the Web in 2024) and Microsoft Project Plan 3 or Plan 5 desktop licenses.

For a PMO that used Project Online primarily as a lightweight task tracker with basic Gantt views, this path is probably workable. For a PMO that depended on Project Online's enterprise capabilities, the gaps are significant.

Capability	Project Online	Microsoft Planner (2026)	Project Plan 3/5
Enterprise resource pool	Yes	No	No
OData API / reporting endpoint	Yes	Limited	No
Timesheet workflows	Yes	No	No
Stage-gate governance / PDPs	Yes	No	No
Cross-portfolio rollup and capacity	Yes	Limited	No
Critical path analysis	Yes	No	Yes (single project)
Baseline tracking	Yes	No	Yes (single project)
.mpp round-trip fidelity	Yes	No	Partial

Microsoft has signaled that portfolio features will come to Planner "over time," but as of mid-2026 they are not there. Building a cutover plan around a product roadmap that is five months away from your hard deadline is a risk most PMO directors will not accept.

If your organization needs full enterprise capabilities, you are evaluating purpose-built PM platforms. The most commonly evaluated in 2026 are Onplana—designed specifically for this migration—along with Smartsheet for spreadsheet-oriented workflows and Planview for larger enterprises. The full comparison of Microsoft Project alternatives covers the trade-offs in detail.

How Long Does a Project Online Migration Actually Take?

The honest range is 12–16 weeks for a mid-size PMO with 50–300 active projects, a shared resource pool, and custom enterprise fields. Here is where that time actually goes:

Weeks 1–2: Inventory and OData snapshot. Export every active project as a raw data backup. Then inventory your custom fields, downstream OData report consumers, Power Automate flows touching Project Online, and active timesheet periods. This step almost always surfaces 30–50% more migration scope than the PMO's initial estimate. Teams that skip the inventory discover it during the migration.

Weeks 3–4: Vendor decision. Run three or four real projects through each shortlisted platform's import tool. Evaluate on actual data, not demo content. Use the migration cost calculator to build the total cost case for your sponsor.

Weeks 5–8: Pilot. Migrate three to five real projects representing different EPTs and run them in parallel with Project Online. Surface gaps before they become production problems. Recreate one stage-gate workflow, one portfolio rollup, and the resource pool in the destination before declaring the pilot successful.

Weeks 9–14: Staged migration. Migrate active projects in waves of 20–40 per week, grouping by department or portfolio rather than by date. Historical projects should be archived to long-term storage rather than migrated—most tenants archive 30–50% of their schedule catalog at this stage.

Weeks 15–16: Cutover and validation. Freeze Project Online writes. Redirect users. Validate that schedule outputs, utilization numbers, and report values match.

The migrations that fail compress this to 6–8 weeks and skip the inventory phase. They discover mid-migration that they have 120 active custom fields instead of 30, or that an executive Power BI dashboard depends on an OData query nobody documented. The Project Online retirement 90-day action plan walks through week-by-week milestones with specific tasks per phase.

What Should You Do Right Now?

The right action depends on where your organization stands today.

If you haven't started at all: Pull a full OData snapshot this week. Every project, in raw form. This is your insurance policy—if everything else goes wrong, you still have the data. Then read the Project Online end-of-life overview for the full data-impact picture, and get a vendor shortlist together before the end of the month.

If you have started the evaluation but haven't committed: Use the free migration preview tool to run real .mpp files through candidate platforms before committing. Seeing how your actual schedules transfer—dependencies, custom fields, baselines—is worth more than any vendor demo.

If you are mid-migration: Your priority is completing the active-project migration wave before August 2026, leaving September as validation buffer. Archive historical projects in parallel to reduce scope and training load.

If you believe you have until September 30: Reread the read-only window section above. The safe export window closes at August 31, not September 30. The teams finishing migrations on time in 2026 are the ones who started this conversation six months earlier.

The Onplana migration guide covers the full motion—OData import, .mpp import, resource pool reconstruction, and stage-gate recreation—without requiring a sales conversation to access.

Microsoft Project Online™ is a trademark of Microsoft Corporation. Onplana is not affiliated with Microsoft.