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How to Troubleshoot Microsoft 365 Apps Not Working

Maira Mehtab Sep 20, 2026 869 views

Question details

The user needs to know what specific information is required to effectively troubleshoot and diagnose Microsoft 365 applications when they fail to work properly.

Product: Microsoft 365
Device & OS: not provided
Scenario: Diagnosing application failures, crashes, or feature malfunctions.
Observed behavior: Microsoft 365 or its individual apps are not functioning, necessitating a structured troubleshooting approach based on specific error details and system changes.

Before you start

Before beginning the troubleshooting process, ensure you have your Microsoft 365 account credentials handy and verify that your device has a stable internet connection.

Solution 1Recommended

Gather Essential Diagnostic Information

Collecting specific error messages and pinpointing system changes is the critical first step in diagnosing Microsoft 365 app issues.

When Microsoft 365 applications fail to open or work as expected, jumping straight into repairs without knowing the cause can be inefficient. Gathering the right details helps support teams or troubleshooting tools identify the exact root of the problem quickly.

Identify the Exact Problem and Error Message

Note down the exact wording of any error messages or error codes displayed on your screen when you attempt to launch or use the app.

Check App Behavior

Determine whether the Microsoft 365 apps completely fail to open, crash immediately upon launch, or if only a specific feature (like saving or printing) fails to respond.

Review Recent System Changes

Make a list of any recent changes to your system. This includes operating system updates, recent Office updates, modifications to your Microsoft account, hardware changes, or new antivirus software installations.

Why This Matters: Providing these details helps determine whether the issue is caused by a corrupted application file, a conflicting third-party add-in, or a recent incompatible update.

Free Microsoft Office alternative

Switch to WPS Office for a Reliable, Crash-Free Experience

If your Microsoft 365 apps are constantly crashing, failing to open, or causing frustration during critical tasks, consider switching to WPS Office. It is a free, lightweight, and highly compatible alternative that lets you open, edit, and save your documents seamlessly without the hassle of complex troubleshooting.

1. Download the Installer: Visit the official WPS website and download the free WPS Office installation file.
2. Install WPS Office: Run the downloaded file and follow the simple on-screen prompts to install the suite on your device.
3. Open and Edit Documents: Launch WPS Office and instantly open your existing Microsoft Office files to continue your work without interruption.

Fully compatible with Microsoft Office formats, including Docx, Xlsx, and Pptx.Lightweight installation that requires fewer system resources, reducing the chance of application crashes.Familiar and intuitive user interface ensures a seamless migration with zero learning curve.Free to use with powerful built-in PDF editing and conversion tools.

Frequently Asked Questions

Why are my Microsoft 365 apps suddenly not opening?

This can be caused by corrupted application files, conflicts with third-party add-ins, expired subscription licenses, or recent problematic operating system updates. Checking for specific error codes can help narrow down the exact cause.

How do I find the error code when a Microsoft 365 app crashes?

Error codes are typically displayed directly in the pop-up dialog box when an application crashes or fails to activate. You can also find detailed error logs in the Windows Event Viewer under the Windows Logs > Application section.

Will running a repair tool fix apps that aren't working?

Yes, performing a Quick Repair or an Online Repair from the Windows Control Panel (under 'Programs and Features') often resolves corrupted file issues and registry errors that prevent Microsoft 365 apps from functioning correctly.

Is there a free alternative if I cannot fix my Microsoft 365 apps?

Yes, you can use WPS Office. It is a free, lightweight office suite that is highly compatible with Microsoft Word, Excel, and PowerPoint file formats, allowing you to access and edit your files immediately.

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