You can't use the ~ character and get that type of result.
Instead, use this expression:
Get ( DesktopPath ) & "untitled.xlsx"
When I tried either of the the following as the output file there was no error message but also no file created:
filemac:Get ( DesktopPath ) & "untitled.xlsx"
filemac:Get ( DesktopPath )untitled.xlsx
When I tried the following and got the same error message I reported in my original post:
filemac:Get ( DesktopPath )/untitled.xlsx
Apologies for leaving out a key detail.
You'd do it this way:
Set Variable [$Path ; "file:" & Get ( DesktopPath ) & "untitled.xlsx"]
Then use $Path as the "file" to which you are exporting.
Thank you, that works!
It seems unnecessarily convoluted, but it does work.