SOLUTION Some user experienced SD removed unexpectly after updating there phone so i made this thread. Commonly problem ito sa Galaxy Y. Step: 1. ROOT your phone 2. Install and open Root Explorer 3. Edit files in the folder/ sys/devices/virtual/bdi/179: 0/read_ahead_kb by pressing and holding the read_ahead_kb then choose open in text editor. note: Other phones don't have 179:0.. but is ok 179:8 4. Replace the numbers in it from the default (128KB) to 1024 / 2048 / 4096 (according to taste max = 4096) and then save and exit. 3. read_ahead_kb Navigate the file again and select the permissions or hide tick marks on the User -> Write.