OneDrive File Issues

Fix OneDrive Sync and Excel File Format Errors on Mac

Maira Mehtab Sep 22, 2026 869 views

Question details

The user needs to resolve OneDrive synchronization failures and Microsoft Excel errors indicating that the file format does not match the file extension on macOS.

Product: Microsoft Excel, OneDrive
Device & OS: macOS
Scenario: Attempting to sync or open Excel files stored in OneDrive on a Mac.
Observed behavior: OneDrive fails to sync, and Excel displays a prompt stating the file format does not match the file extension, preventing the user from opening the document.

Before you start

Ensure your macOS is fully updated, and verify that your Microsoft account has an active Office license linked to it before performing any software reinstallations.

Solution 1Recommended

Check macOS System Privacy and File Permissions

Grant Microsoft applications the necessary folder access in macOS settings to bypass system restrictions causing sync and format errors.

Major operating system updates, such as macOS Sequoia, frequently reset application permissions. This can silently block Microsoft 365 apps from reading or writing files properly, leading to false 'file format mismatch' errors and OneDrive sync stalls.

Open macOS System Settings

Click the Apple menu in the top-left corner of your screen, select 'System Settings', and navigate to 'Privacy & Security'.

Verify Files & Folders Access

Click on 'Files & Folders' in the right pane. Locate Microsoft Excel and OneDrive in the app list, and ensure the toggles next to your standard folders (like Desktop, Documents, or Downloads) are switched on.

Check Individual File Permissions

Open Finder, locate the problematic Excel file, right-click it, and select 'Get Info'. Scroll down to 'Sharing & Permissions' and ensure your specific user account has 'Read & Write' privileges.

Solution 2

Perform a Clean Reinstall of Office for Mac

If permissions are correctly configured but errors persist, remove corrupted Office installation and license files before reinstalling.

Free Microsoft Office alternative

Switch to WPS Office for a Seamless Mac Experience

If Microsoft Excel continues to give file format errors or OneDrive sync issues on macOS, try WPS Office. It is a free, lightweight, and highly compatible alternative that works flawlessly on Mac without complex permission setups.

1. Download WPS Office: Visit the official WPS website and download the free installer specifically designed for macOS.
2. Install and Launch: Follow the simple installation prompts and launch the application. You can sign in to enable integrated cloud backup.
3. Open Your Excel Files: Drag and drop your .xlsx or .xls files directly into the WPS Office interface to continue working without format mismatch errors.

Fully compatible with all Microsoft Excel file formats (.xlsx, .xls, .csv).Lightweight application that runs smoothly and quickly on macOS.Familiar tabbed user interface ensures a zero-learning-curve migration.Free to use with built-in cloud sync to avoid system permission conflicts.

microsoft office alternative - wps office

Frequently Asked Questions

Why does Excel say the file format and extension don't match on Mac?

This error generally occurs when the file extension has been manually altered, the file is corrupted, or macOS permission restrictions are blocking Excel from reading the file structure correctly.

How do I fix OneDrive sync issues after a macOS Sequoia update?

macOS updates can reset application privacy settings. You need to go to System Settings > Privacy & Security > Files & Folders, and verify that OneDrive has permission to access your local directories.

Will I lose my Excel files if I uninstall Office for Mac?

No. Uninstalling the Microsoft Office applications (like Excel or Word) only removes the software. It will not delete your documents, workbooks, or any files stored in OneDrive or local Mac folders.

Document & File Issues