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Thank you for your question. I will do my best to assist you.
May i connect with you remotely to troubleshoot the issue directly? Thanks
Go to the Mac's Finder.Find the file type you'd like to open with a specific app, and select it.Click on the File menu and select Get Info.Expand Open with: by clicking on the triangle to the left.Select the Open with: menu, then choose the app you'd like to use to open all documents like that one. (the new excel application)Click the Change All... button.You'll get a dialogue box asking you to confirm your choice. Click Continue.Close the Get Info window.Now, double-clicking on those files will cause the new application to open, instead of what happened before.