Warning messages are displayed in yellow and are related to possible work flow which may or may not comply to company policy. Error messages are displayed in red. The condition or advice in the message should be acted upon to continue working on a screen.
Error messages may occur when mandatory fields are not filled in or are not filled in correctly. Error messages may also occur exiting edit mode (without saving changes).
When the pencil is shown in a tab on a form, something in that tab is still in edit mode and not saved. Switching to another tab in that form is possible, but exiting the screens when a pencil is displayed in a tab will cause an error or warning message.
Error messages may also occur when entering data in a specific sequence is not followed. For example, data for an invoice cannot be extracted from a contract for which costs have not yet been saved. A Sales delivery from Inventory cannot be fulfilled when the physical goods have not been booked into the warehouse from the original Purchase to Storage delivery.