Comment 3 for bug 635992

> Actually blank just means that it defaults to your %TEMP% directory.

IMHO this is not a viable solution if the 'Autosave' option is to be enabled by default: on Mac OS X for example the directory for temp files is not directly accessible by the average user without knowledge about shell variables and about how to enter commands in the terminal. (See bug #570695)

A -by default- enabled autosave directory needs to be easily accessible on all supported platforms, without having to resort to the terminal to figure out the paths (of %TEMP%, $TEMP, $TMPDIR or $TMP) and which one is actually used on the local system - even more so as long as the autosaved files can't be accessed from within Inkscape itself. (See bug #171424)

Prerequisite to this would be that the (default) autosave directory is created by Inkscape if it doesn't exist. (See bug #490338)