A single user has created a filter or power filter, saved the filter and set it as a default filter.  Now the portlet will no longer load.  The progress circle in the browser just keeps spinning.  

Unfortunately, this can only be fixed by using a database query.

Release:
Component: ODSTU

Steps to fix this issue:

If this is an On Demand Case, Product Support should handle steps 1 - 6, and On Demand should handle running the query in step 7 to delete the filter row.

If you are an On Premise customer, please contact Technical Support before you run the delete query to make sure this is the correct resolution for your problem.

1.  Determine the name of the portlet.
2.  Go to Administration, Portlets.  Locate and open the portlet to the properties page.
3.  Record the portlet id from the URL.  You will see "portletId=xxxxxxx"  where xxxxxxx is the number/portlet id you want.
4.  Go to Administration, Users (or Resources) and locate and open the properties page for your problem user. 
5.  Record the user id from url.  It will be the number after id=.  Do not choose the one after resourceId=
6.  Now run the following query.  It should return only 1 row:

select * from cmn_attribute_value_sets
where created_by = xxxxxxx
and view_code = 'yyyyyyy'
and is_default = 1 

where xxxxxxx is the number recorded in Step 5 and yyyyyyy is the number recorded in Step 3.  

NOTE:  The apostrophes are required in the and view_code= line.

7.  Run the following query to delete that filter:

delete from cmn_attribute_value_sets 
where created_by = xxxxxxx 
and view_code = 'yyyyyyy' 
and is_default = 1;

where xxxxxxx is the number recorded in Step 5 and yyyyyyy is the number recorded in Step 3.  

NOTE:  The apostrophes are required in the and view_code= line.