sim processing error please help error pops up right before shutdown and right after powerup but only for a second then goes away. phone seems to work okay but what is this? how do I fix this?
You shouldn't worry about it too much unless it was lasting too long. When you switch your phone on or off, the SIM is not detected yet (when switching on) or no longer detected (when switching off), that's why you get the error message. When it is detected and connected to your service provider, the error disappears.

If the error becomes permanent, then you will know that your SIM card probably is faulty and should be swapped to a new one.