Another problem we sorted out while developing with magento is after installation of magento 1.4 with sample data, all categories are showing up but when you view the categories it doesn’t show the products under the categories.
If you are the one who stuck up with the same problem follow the instructions and your problem would be solved.
1. Goto your admin panel, select System->Index management, Select all and select “Reindex data” from actions drop down and click on submit. It would take some time to re index it, once its finished. Go to front end and see your products are listed now.
If your products are not listed follow the remaining steps,
2. Goto admin panel, System->Manage Stores, Select the store name, by default it would be “Main Store“, Click to edit it, on the edit screen, See to it that “Root Category” points to your root catalog, ie., All the categories are been formed under this root catalog.
If its not pointing then make sure it points to your real root catalog. Then click on “Save Store” .
Now if you clear your cache and look your front end, you would see your products listed on the desired categories.
Please leave your thoughts as comments.