This seems to be a huge problem, one that has appeared in the last three years. I have just checked my tax summary on here (I have an accountant who would usually do this so I haven't looked - I know, I know) and can see huge amounts in the disallowed section under various headings. When I click on the amount that is disallowed I don't get to see a breakdown of what has been disallowed, just all of the transactions under that heading. It is very obvious, however, that all of the transactions in the section should be allowed. I am really worried now that for the last three years I have overpaid my tax due to QB incorrectly categorising items as disallowable. It seems to be crazy that Quickbooks just assigns them with no apparent logic!