Android Emulator Issue

Yesterday I resumed the work on improving the Packing List 1.5. However, the Emulator didn’t corporate. It kept crashing. I was so frustrated. I deleted and re-created the image several times. It still didn’t work. The error I received was something like "sad result from adb". What does “sad result” mean? They really should give it better description. Some times I received “the user data image is used by another emulator” while there was only one emulator and one user. I googled and no help. Finally, this morning I tried again, the emulator was so slow to start. So I checked the power mode on my laptop. It turned out I accidently set the power mode to “Power Saver” a couple of days ago. I changed it back. Now everything worked just fine!