If you've built a report in Cloudability that includes a tag column then it's likely you've seen a row called "(not set)".

This could mean one of three things: 

1. You have not told AWS to include all of your tags in your Cost Allocation file. See Section 2 of this help article for how to include AWS tags in cost allocation files.
2. You have resources that are taggable but are not yet tagged. 
3. You have AWS spending that is simply not taggable. Common examples are Support Costs, upfront Reserved Instance fees, Tax and EBS snapshots.

Due to #3, you'll likely have at least some "(not set)" in your account.  You can exclude it from your reports by adding a "not equals" filter for that tag with the value of "(not set)".  

See the example below on how to achieve this.