System solutions in MS Dynamics CRM

In storage model description was described, how different types of solutions affect component storage in system. And only one system solution was mentioned: "Active solution", but it's not alone in CRM system.

System solutions

There are four standard solutions in any CRM organization

• System – Internal CRM System Solution, all components from default CRM
  installation placed here
• Active – Placeholder solution marker for all customizations for any components
• Default – Solution that contains all components in the system, it opens after
  “Customizations”->“Customize the System” link click
• Basic – Placeholder solution marker for all those components that do not and
  should not belong to any other solutions

"System" solution acts like managed solution. When new organization is created, it contains "System" solution with all basic entities (e.g contact, account, incident etc). According to storage model of solution components any changes in component leads to creation of new row for this component in "Active" solution. Customizations of system cannot affect base system components, but also them can't be reverted.

"Default" solution is just a holder for all components to make possible to display them when system customizer clicks “Customizations”->“Customize the System”.

"Basic" solution holds components, which should not be shown even to system customizer, for example workflow execution instance, every time workflow is changed its copy is created and stored in this solution, to support finalization of execution of workflows, which had already been started for some entity instances.