Identify the queries that use the attribute category and either remove the attribute or delete the queries,

To locate the affected queries, use the following:

select * from adhocquery

where cast(querydefinitionxml as nVarchar(Max)) like '%ATTRIBUTE57215A3DCDEB4DE9934B9026B19807D8%'

The attribute ID is the "ID" field for that category in the ATTRIBUTECATEGORY table.