You need to have some place for Calibre's executables and libraries and stuff.
You could run Calibre off of a thumbdrive to get these off your your SSD.
https://www.mobileread.com/forums/sh...d.php?t=333990
You can get a 240Gb SSD for only a little more than a thumbdrive. That's a significant increase over your current 16Gb SSD, which must be quite old. Replacing the SSD would be my recommendation.
http://www.amazon.com/Kingston-240GB...53&sr=8-3&th=1