I am having an issue showing columns other than System Columns in the report builder. As you can see from the attached I have my sheet selected. What am I missing? I tried saving and going back in, but this did not fix this situation.
It looks like you may have selected to build a Summary Report based off of Sheet Summary fields. If you are trying to build a report from data stored in the rows of the sheet itself, you will want to build a Row Report.