Good afternoon rrucksdashel

Linked formulae are not the only place where links to external workbooks can hide. Named ranges can be linked to other workbooks, and also objects (such as comboboxes, textboxes etc) can also contain links to other workbook. Beware with named ranges because those with links to other workbooks quite often don't show in the named range dropdown box (top left of your working area) you have to go to Insert > Name > Define.

My free add-in via the link below can help you find awkward links, but at the present it doesn't support links hidden behind objects - I'm working on it.

Excel does have a reputation for having a bug that tells you that a workbook has links when really it doesn't, but I personally have never known it be wrong - many users don't realise that links can hide among other objects than formulae.

HTH

DominicB