"The import of solution: [solution name] failed" error occurs in Dynamics 365

When attempting to import a solution in Dynamics 365, you encounter the following error details:

"The import of solution: [solution name] failed."

Within the Detail column of the grid, you see the following message:

"Fields that are not valid were specified for the entity."

If you click Download Log File, you see a message similar to the following:

"Attribute [attribute name] is a Boolean, but a Picklist type was specified."

You also see a reference to error code 80041A06.

This error can occur if you had previously created a field (attribute) of a certain data type and later try to import a solution that contains the same field name but with a different data type.

Example: You create a field called CustomField1 with the Data Type set as Two Options (Boolean). If you try to import a solution with the same field name but a different Data Type such as Option Set (Picklist), you will encounter this error.

If you are intentionally trying to import the same field with a different type with the goal of changing the type, this is not supported. For example: If you created a field of a certain type and later decide you want to change the type, you would need to use one of the following options:

1. Create the field with a different name in the solution you are trying to import. After you create/import the field with a different schema name, you can migrate the data (if needed) and then delete the previously existing field (if no longer needed).

2. Delete the existing field in the organization where you are trying to import the solution. IMPORTANT: This option should only be used if you do not need to keep the existing data in this field.