|   utf-8: 日 本 語 こ ん に ち は
| The first problematic character is at point in the displayed buffer,
| and C-u C-x = will give information about it.
| 
| Select one of the following safe coding systems, or edit the buffer:
|   shift_jis euc-jp iso-2022-7bit compound-text-with-extensions
| Or specify any other coding system
| on your risk of losing the problematic characters.
\----

Why doesn't it allow me to use utf-8?
-- 
file-error; Data: (Opening input file no such file or directory ~/.signature)