Got below error message in the import log when trying to import data into to existing users profile. I had the overwrite option set and the username was in the source file and mapped. However b not the email, must the emails also be set/imported?
**** Error attempting to add record:1 The parameter 'Email' must not be empty. Parameter name: Email at System.Web.Util.SecUtility.CheckParameter(String& param, Boolean checkForNull, Boolean checkIfEmpty, Boolean checkForCommas, Int32 maxSize, String paramName) at System.Web.Security.SqlMembershipProvider.UpdateUser(MembershipUser user) at System.Web.Security.MembershipUser.Update() at System.Web.Security.Membership.UpdateUser(MembershipUser user) at DotNetNuke.Security.Membership.AspNetMembershipProvider.UpdateUserMembership(UserInfo user) at DotNetNuke.Security.Membership.AspNetMembershipProvider.UpdateUser(UserInfo user) at DotNetNuke.Entities.Users.UserController.UpdateUser(Int32 portalId, UserInfo objUser) at DataSprings.DNN.Modules.UserImport.UserImportProcess.DoUserImport()