User set permanent file export settings in SAP OR Remove SAP ALV Settings for User
How user set settings?
User clicked on Export icon

Selected Spreadsheet option (Or any other option)

User selected checkbox “Always Use Selected Format”

When next time user try to export SAP GUI will not ask what Formats they want to save
Solution:
Run SA38 TCode

Run Report : SALV_BS_ADMIN_MAINTAIN

Select : User-Specific Settings for SAP GUI ALV

Remove user from list

Continue

Now doing this user will able to select Formatting option again