Why are some of my products not exported in the feed ?
When you open up the XML file, if you observe that some products haven't be exported, this may be due to general product exclusion rules that have been set up incorrectly(*).
In the "Product exclusion rules" tab of the module "Feed management" section, check the values filled in:
In the example above, products without EAN13/JAN or UPC aren't exported, nor products without manufacturer reference (MPN). Select "No" for these two options in order to export these products and save:
You should get all your products this time, unless you have defined advanced exclusion rules. In that case, please refer to this documentation.
(*)Please note that the number of products shown in the progress bar when you generate the feed is based on the number of active products in your store (and belonging to the categories/brands you selected in the "Export Method" tab of the module). So, this count doesn't take into account the products you have chosen to exclude. This is why the number of products exported in the XML file isn't necessarily equal to the count you get in the progress bar.
If NO product is exported in the feed XML file, it may be a writing permission issue. In that case, please ask your webmaster for changing this permission in order to make it editable.