Missing Save As Add-in option

[Rhythm]

When I try to save my .xlsm file as an Add-in using the Save-As menu command,
the .xlam Add-in option is missing for some .xlsm files but present for other
..xlsm files. Why is this save filetype Add-in not always present?
Any ideas?

 

[Rhythm]

Found my own solution. The active sheet must be a WORKSHEET when performing a
File Save As in order to find the Add-in filetype. My workbook had both
worksheets & and old dialog boxes.