The Warning tab shows any possible warnings that may exist for the material, the work center / operation and information about the warning, for all the selected parts.
The total number of warnings appear at the bottom of the list. The warning lists mainly manage errors from the Preparation, such as if no cost factor has been configured, or if the setup time/unit time is missing. You can also see warnings about material prices that are outdated and that have not been revised for a long time. However, this option is only shown if you have entered a date in the Oldest price field under the Create tab.