A duplicate attribute key has been found

A fairly common error in SSAS: Analysis Services Execute DDL Task: Errors in the OLAP storage engine: A duplicate attribute key has been found when processing

Reason? The most common one is special characters in a dimension attribute string. The solution is to modify the sql code that loads your data to remove such strings like this:

REPLACE(REPLACE(REPLACE(ColumnName, CHAR(9), ‘’), CHAR(10),’’), CHAR(13),’’)