Have you ever gotten an Error – Unexpected Error has occurred when submitting your exclusion filter settings to your User Profile Service connection? Check and make sure you don’t have a filter looking for a blank property.
When you set up your exclusion filter for your UPS connection, setting an exclusion rule for something like company equals an empty string (see screen shot) you’ll get this error when clicking ok.
Its rather deceiving as it will let you add the rule on the page, but only error on clicking ok. We ran into it after defining about 6 different exclusion rules, clicking ok, and getting an unexpected error. We had to go through our rules one at a time until we realized it was just the blank rule.
So, instead of checking for a blank string, you should use the “Is not present” rule, if looking for a blank field in your user profile service connection.