I haven't run into that yet, but it probably is dependent on how it's installed. The default install for 365 is Click-to-Run, so it's installed in a user-centric (instead of machine-centric) way, which means the registry and folder structure is different. For example, the base Office 2016 install is at C:\Program Files (x86)\Microsoft Office\root\Office16, whereas it used to be at C:\Program Files (x86)\Microsoft Office\Office16. As a science experiment, i wonder if it works if you copy EXCEL.exe to the 'old' path.