Hi...

Before deleting, can you keep a backup on your computer or SD card the file: user.upoi

from --> save/profiles/01/users/00/user.upoi

and then delete...
open the iGO and set it again... for creating new save folder, and then put it back (user.upoi) in the same place...

about the altimeter... the information is taken from GPS and normally is correct.
but i have not search it more...