I have upgraded SAS Enterprise Guide from 7.1 to SAS Enterprise Guide 8.1 on number of Windows 10 machines. When I go into default programs and try to change the .SAS files etc to launch from SAS Enterprise 8.1 I do not get the option to set SAS Enterprise 8.1 as the default program.
If the install on the local machines was done with most of the defaults the SAS folder in that windows software pile(whatever they call it) from the Start Icon should have something with a name similar to SAS Deployment Manager. Use that to change file associations.
Under Administration Tasks you should find an option like Manage SAS File types, select that then click on the Next button.
You should have the choice of setting the default for all the SAS files to either Base SAS or Enterprise Guide. If you want a mix of defaults then use the Advanced to set the default for each file extension.