The import solution raises an error when you have the same entity name that is created in different organizations, and this entity name exists in multiple solution files.
Sample scenario- Create an organization, add a solution that is named "Sol1," and then add a custom entity that is named "new_MyCustom."
- Export the Sol1 solution.
- Create another organization, add a solution that is named "Sol2," and then add a custom entity that is also named "new_MyCustom."
- Export the Sol2 solution.
- Create a new organization, import the Sol1 solution first, then import the Sol2 solution to the organization that you created.
Even though these custom entities have the same name, they have different GUID for Views, Forms, and so on. This is because they were created in different organizations. Therefore, when you import the second solution, the system identifies the GUID difference for same entity, and the error that is mentioned in the "Symptoms" section occurs.