There are numerous Q&A's for Excel WINDOWS, but none for Excel MAC that specifically answer this question.
Using Excel Mac 2011 VBA, how do I open a non-Excel file using the file's default app?
After much research and testing, I figured out the answer. See below.
This works running Microsoft Excel 14.7.2 (14.7.2) on macOS 10.12.6.
```vb
```
For Excel Windows, see
How can Excel Windows VBA open file using default application