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.

If you open the file online, Microsoft 365 will open it on the desktop by default, so you can skip the manual process without worry. To set this default setting, follow these steps.