If you have drywall tape joints that are cracking you will want to fix them to retain the smooth look of your walls or ceiling. Generally, cracking occurs because of a temperature difference between outside and inside or due to settling of the house.
Step 1: Remove Old Tape
Drywall tape that is typically used isn't as flexible as mesh drywall tape. It is best to remove all of the old tape and start fresh. Cut the tape and pull it off the joint. Remove all of it, even the part that isn't cracking. Do this for all the tape.
Step 2: Replacing the Tape
Starting at the top of the joint, press the tape onto the wall covering the joint, making it as even as possible on both sides of the joint. Next, smooth drywall joint compound over the tape and onto the wall along the span of tape. It should be about 4 inches wide. Allow this to dry overnight. The next day, cover again with a smooth coat of compound, about 6 inches wide. Allow to dry at least 10 hours, then cover again—this time about 10 inches wide. Allow it to dry and then sand it smooth.
Repeat this for all of the cracked drywall tape joints.