If you logged into Student Planning and got a red pop-up telling you a hold is preventing you from adding/dropping
you should contact the office that has placed the hold to address it ASAP (even if you don't need to register/add/drop right now, this is still a problem that needs to be resolved before it causes you any future issues!).
You can find out where any holds are coming from via the Barnard Portal, which will take you to the relevant Slate page as follows:
1. Log into the portal,2. Hover your mouse over Academics
3. Then hover over Planning Your Courses
4. Then click Registration Appointment & Holds.
5. This will take you to a Slate page which may ask you to log in with your Columbia UNI before opening. Here you will see any holds as well as a link to a list of all upcoming registration times (more comprehensive than what you see in Student Planning, which just shows your next time, and shows nothing if you log in during a reg time):
