A Microsoft file hosting and synchronization service.
Hello, thank you for reaching out to Microsoft Q&A.
Open the Safari Web browser on your Mac.
Start an incognito tab and sign in with your Microsoft account here-
You can view all your files online and should be able to download them on your Mac.
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Regarding the OneDrive desktop app, could you please share the exact error message you see on the device?
Have you tried uninstalling and reinstalling OneDrive? This may resolve any sync issues you are experiencing.