How to identify the cause of entering Safe Mode?

I have a Motorola Xoom 3G tablet running Android 4.04 (latest system release) that has been stuck in 'safe mode' for some time now no matter how many times I restart the device. I have been through the apps list and uninstalled anything I could remember installing recently but still the problem persists. The device is primarily used as a wifi hotspot with my 3G internet around the house which still works fine - but I would also like to use the screen as an ereader from time to time - which the permanent 'safe mode' message gets in the way of. Is there any way of tracing the cause of this safe mode loop? Alternately is there a way of just getting rid of the 'safe mode' message while leaving it in safe mode?