or change your hosting to something more suitable....
With 10,000 categories which will (eventually) be filled up with products that would mean a high-spec fully dedicated server. A low-end VPS or even low-end full dedicated server just wouldn't do.

Personally, and based on all of my years of experience in eCommerce, I think having 10,000+ categories is just plain crazy - and unnecessary. It just smacks of bad planning. I would advise a rethink and a new business plan and budget commensurate with the number of products intended for sale.

Zen Cart can handle any number of products, but the number of categories should be rethought, and Shared Hosting may simply not be suitable. We do have sites with over 100,000 products on our shared hosting, but we do have to occasionally place restrictions on what site owners may do (for instance, using Easy Populate to try and upload 100,000+ products and descriptions in one big blast).

Vger