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
Sub open_file()
Dim scriptStr As String
Dim hfsPath As String
hfsPath = "~:Documents:Test File To Open From Excel.txt"
'--- Create AppleScript to Open Non-Excel File ---
' (Note: You cannot use POSIX path or POSIX commands)
' So, I have allowed for the tilde in a HFS path
' to mean the same as in a POSIX path: Users Home Folder
scriptStr = "set hfsPath to """ & hfsPath & """" & vbNewLine & _
"if (hfsPath starts with ""~"") then" & vbNewLine & _
" set homePath to (path to home folder) as text" & vbNewLine & _
" set hfsPath to homePath & (text 3 thru -1 of hfsPath)" & vbNewLine & _
"end if" & vbNewLine & _
"tell application ""Finder"" to open file hfsPath" & vbNewLine & _
"return hfsPath"
Debug.Print scriptStr
'--- Execute AppleScript to Open Non-Excel File ---
hfsPath = MacScript(scriptStr)
Debug.Print hfsPath
End Sub
```
For Excel Windows, see
How can Excel Windows VBA open file using default application