I have a lot of products and have been trying to get the Search Filter to work to search specific products within individual categories.
eg. There are 500 products in a particular category in the shop and the pagination shows the correct number of pages for the 500 products, but only page 1 of the search results actually shows the products - page 2 of results onwards show no products at all.
I had this problem, it was a Jquery conflict issue. Turn on jquery in VM2 and turn it off on any other modules etc
go to Configuration > Templates > Under Activate Css Styles & Javascripts (bottom right) and tick Using the VirtueMart jQuery