The reason it is asking you if you want to delete all is because you have not selected specific files to erase, so when you hit erase without selecting a file it assumes you mean delete all.
To erase try these steps...
To erase a selected file from Folder A, B, or C:
- Press the MENU/FOLDER button to select Folder A, B, or C.
- Press the - or + button to select the file to be erased.
- Press the ERASE button.
- Press the - or + button to select YES.
- Press the ENTER/INDEX button.
To erase the contents of Folder A, B, or C:
- Press the MENU/FOLDER button to select Folder A, B, or C.
- Press the ERASE button twice.
- Press the - or + button to select YES.
- Press the ENTER/INDEX button.
To erase a selected file from a date subfolder in Folder S:
- Press the MENU/FOLDER button to select Folder S.
- Press the - or + button to select the date subfolder.
- Press the PLAY button.
- Press the - or + button to select the file to be erased.
- Press the STOP button.
- Press the ERASE button.Press the - or + button to select YES.
- Press the ENTER/INDEX button.
To erase the contents of a date subfolder in Folder S:
- Press the MENU/FOLDER button to select Folder S.
- Press the - or + button to select the date subfolder to be erased.
- Press the ERASE button twice.
- Press the - or + button to select YES.
- Press the ENTER/INDEX button.
To erase the contents of a month subfolder in Folder S:
- Press the MENU/FOLDER button to select Folder S.
- Press the ERASE button three times.
- Press the STOP or PLAY button to select the month subfolder to be erased.
- Press the ENTER/INDEX button.
- Press the - or + button to select YES.
- Press the ENTER/INDEX button.
To erase the contents of Folder S:
- Press the MENU/FOLDER button to select Folder S.
- Press the ERASE button four times.
- Press the - or + button to select YES.
- Press the ENTER/INDEX button.
PS. here is a link to download manuals and software for this device:
http://www.olympusamerica.com/cpg_section/cpg_support_product.asp?id=1080
Good Luck ... oh and dont forget to rate my response.