I assume you mean to have Query7 be UF.
Is your Query7 a Union query?
Becuase using the code:
UPDATE UF INNER JOIN [Input List] ON UF.number=[Input List].number SET [Input List].status = "a";
Gives me the error: Operation must use an updatable query
UPDATE [Input List] INNER JOIN UF ON UF.number=[Input List].number SET [Input List].status = "a";
gives the same issue