Enable Flat Catalog for products and categories
Using Flat Catalog Category and Flat Catalog Product is a great solution for optimizing Magento store. This will help to reduce queries to database a lot and improve the speed and quality of the Google Shopping output.
Access to your Magento Admin Panel then System > Configuration > Catalog > Catalog > Frontend
When flat catalog is enabled in Magento then all the above product attributes (id, name, price) are kept in one table named like catalog_product_flat. Then Magento fetches product data from the flat table rather than joining all the other smaller tables.
You have to rebuild Flat Catalog using Cache Management and Index Management. The extension can be used with the flat catalog disabled but due the performance and the certainty of the data output we recommend to enable it.
If your missing data in the output with the flat catalog disabled please use the bypass flat catalog function in the Advanced tab.
Attributes in the Flat Catalog
If there are attributes used that aren't part of the flat catalog you can easily add them using the add function in the notification.
Old version or overwrite detected
This notification tells that you have an old version in the app/code/local/magmodules/googleshopping folder. As the new versions are located in the app/code/community/magmodules/googleshopping folder this could cause a conflict with these 2 versions. If this notification shows up we recommend to remove the version in the app/code/local/magmodules/googleshopping folder and refresh your caches.
Magento depends heavily on its cron. As of Magento EE 1.14.1 and Magento CE 1.9.1 all Magento e-mails (including order confirmation and transactional) are sent by cron.
It's also used for tasks as: DB log cleanups, sending newsletters, generating Google Sitemaps, etc. However, many people forget to set up this cron.
You can check if the cron is running by checking the the cronjob timeline using the AOE Scheduler extensions. With this extension you can manage, view and test your scheduler/cron tasks including a timeline. You can download this extension right here.
Module Output Disabled
Make sure the Module output for the Google Shopping extension is enabled under the System - Confiugration - Advanced - Advanced Tab in the Magento Back-end .