[Zen Cart] What is this "/-1/" instead of /category-1/?

[echazen]

please see this site:

http://www.tech-products.com

when you navigate to a product page, there is a portion of the URL with this in it: /-1/

how did that appear and how can i get rid of it?

[inveo]

This happen when your product is assigned to category which has no name specified.

Try to set use_master_category to false in includes/msu_tweak.ini file (it looks like you are not currently using master categories but were used some time ago, so some database records are now missing).