Mouse and keyboard freezes with Arduino Uno and IDE 1.6.5 (and 1.6.6).

Good afternoon, thank you in advance for your responses.

I'm starting with Arduino and I tried to upload the sketch 'blink' on Arduino. In the IDE 1.6.6 the program detects my Arduino Uno in the USB port but when I try to upload the sketch, mouse and keyboard (both connected by Bluetooth) disconnect and the program freezes the upload. The only solution to recover the control of the computer is rebooting it.

All it's done with an iMac mid-2007, OS X El Capitán. I've tried to reinstall Arduino IDE and disabling System Integrity Protection and Kext and now I don't know what to do (reinstalling OS X at the moment).

Sorry if it is solved in other post, at least I've not seen it :confused:

Thank you in advance! Tinsvoia.