At the moment, SIS-integrated student extractions are inoperable for domains consisting of multiple schools and using PowerSchool integration. If a school using PowerSchool integration tries to load students, the data loader will show that no new or changed students could be found.
We believe that we have found the cause of this problem, and we are working to fix it as soon as possible. Until then, our team can help load student data in particularly urgent circumstance. If you would like us to help you load students, simply let us know.