MS CRM Attribute Mapping Error When Importing Customizations
Failure: Entity-Entity: This attribute map is invalid. A valid attribute map must meet these requirements: -	The data type must match. -	The length of the target attribute cannot be shorter than the source attribute. -	The format should match. -	The target attribute must not be used in another mapping. -	The source attribute must be visible on the entity form. -	The target attribute must be a field a user can enter data into. -	Address ID values cannot be mapped.
This can be a number of thing however, in my case it was attributes that were mapped differently than expected. To resolve it I had to open the Customization XML file and review the mappings there were bring created, comparing then to the CRM instance. By then deleting the inconsistant ones on the tenant the XML file then imported correctly.