`nnmail-active-file-coding-system'.
(defun nnmail-save-active (group-assoc file-name)
"Save GROUP-ASSOC in ACTIVE-FILE."
- (let ((coding-system-for-write nnmail-active-file-coding-system))
+ (let ((coding-system-for-write nnmail-active-file-coding-system)
+ (output-coding-system nnmail-active-file-coding-system))
(when file-name
(with-temp-file file-name
(nnmail-generate-active group-assoc)))))