What should one do if they lose count of their الطواف circuits?

If a person is uncertain about the number of circuits completed, they should base their count on the lesser number about which they are certain. This is the view of the majority of scholars. الشيخ ابن عثيمين said: 'Build upon certainty, which is the lesser number.' For example, if uncertain whether 5 or 6 circuits were completed, assume 5 and complete 2 more. الشيخ ابن باز added: 'The principle in Islamic jurisprudence is that certainty is not overridden by doubt' (Fatawa ابن باز, vol. 16).