X-Cart's built-in Froogle/GoogleBase export module automaticaly removes any products that have HTML embeded in their descriptions. Please check your product desriptions for embeded HTML such as links to other web pages, text formatting like colors or font sizes, etc. If the missing products don't include embeded HTML please submit a support ticket with a complete description of the problem. Include the url of your web site and the name of a few products that should have been exported but were not. One of our technicians will respond as quickly as possible. Remember you must login to the Client Area before you can submit a support ticket.
We suggest a better solution is to purchase and install the Feed Manager Pro add-on and use it instead of X-Cart's built-in Froogle/GoogleBase export module. Feed Manager Pro is highly configurable, letting you decide precisely what you want to export, it can be set up for completely automatic operation and it can generate feeds for 11 online shopping services in addition to GoogleBase.