Missing products when creating product groups

[thecrystalcove]

Hi all

I am trying to creat a product group for my christmas shop. i want to add all the products in this section into a group to create a discount. I have no other product groups currently yet when i go to add the products into a group there are very few appearing despite the section being quite large.
When i click on the section and move it over to the product group it moves just a handful and the missing products are nowhere to be found

Any ideas?

[Duncan Rounding]

Try compacting the database.

[thecrystalcove]

i am wondering if the problem is that many of the products are duplicate products? Even if this is the case it doesnt explain why, if i click on all products, they arent all there.
unfortunately the compact database option did not fix it