When deciding which customizations to export, consider how the exported customization file will be used.
When you import customizations and settings:
Any new items such as entities, fields or views will be added to the installation.
For an unmanaged solution For those with a required security role, an unmanaged solution has no restrictions on adding, deleting, updating, testing, importing, or exporting solution components. A solution is developed as an unmanaged solution. This differs from a managed solution, where you cannot add or remove components., any changes to existing items will overwrite the current item. For a managed solution A complete solution that has been packaged. A managed solution has partial or full restrictions on customizing solution components. Package and export a solution as a managed solution to control customizing solution components when installed into another organization. While a managed solution may allow customizing one or more components, you cannot add or remove a component. This differs from an unmanaged solution, where you can add or remove components., customizations are merged for forms, the site map, and option sets.
These changes can include settings within relationships and event scripts for entities.
If you plan to transfer customizations from this Microsoft Dynamics CRM implementation to another implementation that also is customized, you will overwrite existing customizations if they are different. To avoid this problem, either:
Import all customizations from the target Microsoft Dynamics CRM system prior to performing additional customizations, so that when you export customizations, you'll include existing customizations as well as your new ones.
Only export entities that are not already customized in the target Microsoft Dynamics CRM system.