How to Fix Word for Mac Code Signature Invalid Crashes
Question details
Users are experiencing a crash when launching Microsoft Word for Mac due to a 'Code Signature Invalid' error, while other Microsoft 365 apps continue to work normally.
- Product
- Microsoft Word for Mac
- Device & OS
- macOS
- Scenario
- Launching the Microsoft Word application on a Mac.
- Observed behavior
- Microsoft Word fails to open and immediately crashes with a 'Code Signature Invalid' error message during the startup process.
Before attempting to fix the file system or reinstalling the software, ensure you have saved your work in other open applications, as you will need to run disk repair utilities and restart your Mac.
Repair Mac Disk and Reinstall Word
Use macOS Disk Utility to fix file system problems that corrupt application signatures, then reinstall a fresh copy of Word.
The 'Code Signature Invalid' error usually indicates that macOS detected corrupted files within the Word application bundle. Repairing the startup disk can resolve the underlying file system issue before you replace the corrupted application.
Open Finder, go to Applications > Utilities, and launch 'Disk Utility'. Select your Mac's startup disk (usually 'Macintosh HD') and click the 'First Aid' button at the top to verify and repair disk errors.
Once Disk Utility finishes, open your Applications folder, locate Microsoft Word, and drag it to the Trash to remove the corrupted application.
Click the Apple menu in the top-left corner of your screen and select 'Restart' to ensure all temporary system files are cleared.
Log in to your Microsoft account on the official Microsoft 365 website, download the latest Mac installer package for Word, and complete the installation process.
Test with a New macOS User Account
Create a temporary user profile to determine if the crash is caused by damaged user-specific configuration files.
Switch to WPS Office for a Stable Mac Experience
If Microsoft Word continues to crash or display signature errors on your Mac, WPS Office provides a reliable, lightweight, and highly compatible alternative. You can open, edit, and save your existing Word documents seamlessly without worrying about complex application errors.
- 1. Download the Mac Installer: Visit the official WPS Office website and download the free macOS installation package.
- 2. Install WPS Office: Open the downloaded file and drag the WPS Office icon into your Applications folder.
- 3. Open Your Word Files: Launch WPS Office and open your existing .docx files directly to continue working without any formatting loss.
Frequently Asked Questions
What does 'Code Signature Invalid' mean on a Mac?
This error means macOS Gatekeeper has detected that the application's digital signature is missing, altered, or corrupted. It is a security feature to prevent tampered apps from running, but often happens legitimately due to file system errors or incomplete updates.
Why do other Microsoft 365 apps work while Word crashes?
Each application in the Microsoft 365 suite (Word, Excel, PowerPoint) has its own independent application bundle and digital signature. Corruption localized to the Word application files will only cause Word to crash, leaving the others unaffected.
Will I lose my documents if I uninstall Microsoft Word for Mac?
No, uninstalling the Microsoft Word application by dragging it to the Trash only removes the software itself. All your personal documents (.doc, .docx) are saved separately in your Mac's folders (like Documents or Desktop) and will remain safe.
