My tape always seems to wrinkle when I use the corner roller. Am I doing something wrong or is something wrong with the roller?

Wrinkles usually happen if you start to roll your corners from one end of the corner to the other instead of from the middle. Try starting from the center and working towards each end first, then roll the entire length of the corner once the tape is embedded. If this doesn’t fix it, the problem could be with the roller. Check to be sure that the rollers are turning freely and that there is no dry joint compound preventing them from turning smoothly. This could cause the roller to “drag” the tape and create wrinkles.