unable to use isolate command for the following attached catia part file
6 Answer

we should use but u have done one mistake while doing the tooth of the gear was open profile and please use sketch analysis after doing the sketch.generally rerouted errors will come for isolated element due to the geometric and dimensional set was not reflected to the original one

i guess you want to do multisection solid.
multisection solid is not working right?
problem for that is.. you sketch have several open dude, please close that