You cannot delete the default tune files. You also cannot delete the currently loaded tune file.
Click Method.
In the Acquisition Method window in the navigation pane, click Instrument Setup > SQ.
In the navigation pane, select Tune > Autotune/Checktune.
If needed, click Take. In this image, Take is already selected.
(optional) Open a different tune file. Click to open the Load Tune File dialog. Select a tune file and click Load.
Click . The Delete Tune Files dialog opens.
(optional) To sort the tune files alphabetically, click Sort.
Select the tune file or tune files to delete.
Click Delete.