"Default" = does not have the same meaning as "default on a loan"*. It is not an
error, or your fault, or anyone else's fault. Instead, default means "automatic," that is, in lieu of
your choosing something else manually, the computer will automatically use that address book, that web browser,
that program, or whatever.
*actually, if you "default" on a loan, the bank automatically gets your car, your house or your boat, so it does mean the same thing!