I am experiencing an issue while attempting to import data to an already created table in SSMS (SQL Server 2012). I am using the import utility and when using the 'Edit Mappings' feature, the Destination column is not able to be selected. It usually is a dropdown menu and I can select the column I want to map the Source field to. It just says and I am unable to map.
Most of the time, I do not experience this issue and I am unable to find any correlations on when/why it happens.
I finally figured out why this happens. The cause is having multiple columns in the Source file with the exact same header. Once the duplicate values are edited, mapping will be allowed.