Quick answer
Open PowerPoint first (not the file). Go to File → Open → Browse, click the small arrow next to the Open button, and choose Open and Repair. If the file lives in OneDrive or SharePoint, copy it to a local folder first. Still stuck? Try Safe Mode, disable add-ins, or recover an earlier version.
WHY IT HAPPENS
"Corrupt" often just means blocked or interrupted.
A file that opened fine yesterday rarely breaks on its own. The usual culprits are a presentation that was interrupted part-way through a OneDrive or SharePoint sync, a file downloaded from email or the web that Windows is holding in Protected View, a misbehaving add-in loading before the file, or a genuine corruption after an app crash or storage fault. The good news: nearly all of these are recoverable with tools already inside Office — no third-party software required.
THE FIX
Work through these in order.
- Use Open and RepairOpen PowerPoint but don't open your file yet. Go to File → Open → Browse and single-click the problem file so it's selected. Click the small arrow beside the Open button and choose Open and Repair. PowerPoint rebuilds the file as it opens it — give it a moment. If it works, immediately use Save As to save a fresh copy under a new name.
- Let it out of Protected ViewIf the file came in by email or was downloaded, PowerPoint may open it in a locked, read-only Protected View yellow bar and refuse edits. Click Enable Editing if you trust the source. If it won't clear, right-click the file in File Explorer, choose Properties, and on the General tab tick Unblock near the bottom, then OK.
- Copy the file out of OneDrive to your PCFiles that are still syncing — or only partly downloaded — can look corrupt. In File Explorer, copy the presentation from your OneDrive or SharePoint folder to somewhere local like your Desktop, then open that local copy. If it opens cleanly, the original just hadn't finished syncing.
- Start PowerPoint in Safe ModeHold the Ctrl key while you launch PowerPoint (or press Windows + R, type powerpnt /safe and press Enter). Safe Mode loads without add-ins and extras. If your file opens here, an add-in is the problem — move to the next step.
- Disable add-insBack in normal mode, go to File → Options → Add-ins. At the bottom, set Manage to COM Add-ins and click Go. Untick anything you recently installed, click OK, and restart PowerPoint. Re-enable them one at a time to find the culprit.
- Recover an earlier version or AutoRecover copyIf the current file is beyond saving, reopen an earlier good version. For OneDrive/SharePoint files, right-click the file online and choose Version history. On the PC, check File → Info → Manage Presentation → Recover Unsaved Presentations, or look in your AutoRecover folder for a recent copy.
- Try a repair of Office itselfIf several files won't open, the app — not the files — may be at fault. In Windows Settings → Installed apps, find Microsoft 365 / Office, choose Modify → Quick Repair. This resets Office without touching your documents.
Before you keep clicking — stop working on the original and make a copy first. Repeated attempts on a damaged file can make it worse. If the presentation is important and none of the above brings it back, don't delete it — a good IT provider can often recover more from a copy using specialist tools.
