If Excel Online is not working and you see errors Couldn't Open the Workbook, or Request Was Taking Too Long, then see this post for the fix.

If you are wondering how to open SDR files on Windows 11/10, you can either use the parent tool, SmartDraw, or use an online tool or program.

Learn how to use a Microsoft 365 setting to choose whether to open files in the online or desktop app, giving you full control for each file.