What Is an .MPP File and How Do You Open or Migrate It?
An .mpp file is the file format used by Microsoft Project. It holds your full project plan: tasks, dates, dependencies, resources, and costs. You need Microsoft Project or a compatible tool to open it. Since Project for the Web retired in 2025, importing an .mpp file into Planner now takes a Power App or custom tooling. It is no longer a simple built-in step.
What is an .mpp file?
An .mpp file is a Microsoft Project file. The name comes from "Microsoft Project Plan."
It stores everything in one place:
Task lists and timelines
Task dependencies (what waits on what)
Resource assignments (who does what)
Cost and budget data
Baselines and progress
Think of it as the master schedule for a project. One file can hold years of planning work.
The catch: .mpp is a closed format. You cannot just double-click it like a PDF. You need the right software to read it.
How do you open an .mpp file?
You have a few ways to open an .mpp file. Each has trade-offs.
Method | Cost | Full editing? | Notes |
Microsoft Project (desktop) | Paid license | Yes | The native tool. Full access. |
Third-party viewers | Free or low cost | View only, mostly | Good for a quick look. Limited edits. |
Import into Planner | Needs Power App | No direct import | See the section below. |
Convert to Excel/CSV | Varies | Loses structure | Dates and links often break. |
If you only need to read the file, a free viewer works. If you need to edit or migrate the plan, keep reading.
Why is opening .mpp files harder now?
Microsoft changed the tools around Project. Two dates matter here.
Project for the Web retired in August 2025. It folded into Microsoft Planner. This already happened. It is not a future event.
Project Online retires on September 30, 2026. After that date, your Project Web App data goes away. You must move it first.
Here is the friction. The old Project for the Web let you import .mpp files with a built-in feature. Planner does not. Microsoft confirms that importing .mpp files is not available in Planner. The official workaround is the Planner Power App, once known as the Project Power App.
That means an extra layer of setup. You need Power Platform access. You need the right app configured. For one file, that is annoying. For a whole portfolio of projects, it is a real problem.
How do you import .mpp files into Planner?
The official path uses the Planner Power App. Here are the basic steps:
Get access to the Power Platform in your tenant.
Open the Planner (formerly Project) Power App.
Use its import function to upload the .mpp file.
Map the imported plan to a Planner plan.
This works, but with limits. GCC and government tenants often face clunkier options. Some fields do not carry over cleanly. And you must repeat the process for every file.
For a single plan, you can push through it. For dozens of active projects moving off Project Online, this manual work adds up fast. That is where a migration partner saves time and risk.
What is the best way to migrate your .mpp files?
If you have one small plan, the Power App may be enough. If you run a real portfolio, plan a proper migration.
A good migration does more than move files. It keeps your data structure intact. It maps old fields to new ones. It tests the result before you rely on it.
At Project Made Easy, this is our core work. We have run 250+ deployments and trained 2,000+ project managers over 19+ years. We move your tasks, dates, resources, and costs without losing critical data.
We give you two proven destinations:
Both keep your project data working through the transition. No scramble at the deadline.
For the full picture on the 2026 deadline, see our guide on the Microsoft Project Online retirement and what to do next. To understand the data stakes, read what happens to your data when Project Online retires.
Frequently asked questions
What does .mpp stand for?
It stands for Microsoft Project Plan. It is the native file format for Microsoft Project.
Can I open an .mpp file without Microsoft Project?
Yes, with a third-party viewer. But most viewers only let you read the file, not edit it fully.
Can Planner open .mpp files?
Not directly. Planner does not have a built-in .mpp import. You need the Planner Power App or custom tooling.
Is Project for the Web still available?
No. It retired in August 2025 and became part of Microsoft Planner.
When does Project Online retire?
September 30, 2026. You must move your data before that date.
Do I lose my project data during migration?
Not with a proper migration. A planned move keeps your tasks, dates, resources, and costs intact.
Don't let your .mpp files get stranded
Project Online retires September 30, 2026. Your .mpp plans hold years of work. Move them the right way, without disruption.
See how ready you are with our Migration Readiness Calculator, or schedule a consultation to map your migration with our team.
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