I have a page with approx twenty CQWPs on them, all coming from the same library. It looks fine to me (Admin) but for the Visitor permission group, some boxes are coming up blank - no error message, just nothing! The header is still there and there is no error message. I've checked the library documents and there are no permission problems, and when I recreate one of the blank CQWPs (new web part with the same search parameters and display settings) the Visitor is still unable to see them. This does not appear to be a problem with web parts not set up with these settings. I'm at a loss! Grateful for any help.
So I thought I'd come back and update you all since it is a very silly thing - I was selecting a bunch of documents and using the 'check in' box in the ribbon to do a sort of 'mass check in' but guess what! It only checks in, it doesn't 'publish as major version', so it wasn't pulling through to the CQWP for Visitors as it was a minor version, which they can't see. So that's what was wrong! Stick like six forks in me, I am done.