Have you made bread or thick cookie dough recently?
If you have been mixing a dense mixture for several minutes or more, it is possible that the force of the planetary action can over-tighten the bowl.
- Place a wet, warm towel around the bottom of the bowl for 10 minutes. Re-warm it after the 10 minutes, put it on again, and let it sit for 1 -2 more minutes. This will re-warm the stainless steel, causing it to expand. After this time, try to wiggle and remove the bowl.
- Try applying mineral oil on the bottom of the bowl near the crease where the bowl attaches to the base plate. The mineral oil may lubricate the bowl enough to allow it to come loose. If you do not have mineral oil, use a vegetable oil cooking spray instead. If you use vegetable oil, make sure to clean the base plate very thoroughly after the bowl is removed, because vegetable oil can become very sticky over time.
- If none of these techniques work, you may wrap the bowl in a towel and GENTLY tap the handle with a rubber mallet.