Lateralus is their only weak album, but its understandable since they fell into the classic trap of every member starting to fiddle with his own hobby projects, allowing Tool to become a sorts of side thing where they book a studio for 3 months every 3 years to pull a new record out of their asses. It was a lot the record companies fault to, since they were unable to produce any albums during the lawsuit that lasted 2-3 years.
Further proof that no band, no matter if theyre the best ever, can make good albums during a period longer than 10 years. So..
R.I.P Tool 1992-2001