The Fix

First go to Control Panel àInternet Options > trusted sites ? and add your URL for Sharepoint.

Then login to your SharePoint (I used Firefox) and pick a document from > Documents > all > and I picked one at random that was an excel document

Once it opens click > Edit workbook > Edit in Excel > which should start to open the document in your local copy of excel (If you get a message about it being blocked click allow and allow and remember.)

But wait, I got this popup (which is actually an add-on for Excel). Help Document Link
So I just went ahead and picked the top option “Microsoft Office 2016” in my case (I wouldn’t use Choose and then pick Excel because that causes other issues.)

After I did that Microsoft Office asked me for a username and password to sign in.
So at the sign in screen I entered my e-mail that I use with Sharepoint
Which prompted this next screenshot. Maggie uses a Microsoft account where I use a work account so it’s important to choose the right type of account.
After you pick the right account type and sign in with the same information you use for Sharepoint and then the document should magically open.