I dropped every Microsoft and other Subscription products years ago and from experience with some others, uninstall and re-install the older product, is the answer. Of course as companies change to cloud based and no disks, that's less and less likely.

Here's what I use now. http://www.openoffice.org/download/

Open Office which is FREE. You can open any type of files and convert it to Open Office format, maybe save in the old formats, I haven't done much except Excel and Word files.