# How to prevent people connecting external HDD to my mac



## ash1111 (Mar 14, 2012)

I have an iMac running snow leopard - I have some confidential files on my computer and need my colleagues to use my computer to work on these files. I would like to prevent my colleagues from connecting a hard drive or usb flash drive to my computer which could enable them copy my confidential files. I can prevent them burning a cd/dvd or using bluetooth or email apps using parental controls (via guest account) but is there a way I can prevent them from connecting any external drives to my computer?


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## Rits (Dec 29, 2011)

Disabling USB devices in OS X, specifically storage devices. This can be done by moving the file "IOUSBMassStorageClass.kext" located in System/Library/ Extensions (replacing the kext restores USB function to normal). 


The Terminal command are: 

sudo mv /System/Library/Extensions/IOUSBMassStorageClass.kext / 
[destination path] 
and (theoretically) for FireWire: 
sudo mv /System/Library/Extensions/ 
IOFireWireSerialBusProtocolTransport.kext /[destination path]
sudo mv /System/Library/Extensions/IOFireWireSBP2.kext /[destination path] 
Note: there is a space between "kext" and the slash; leaving the destination empty will drop the file at the root level of the hard drive. Restart, and test all peripherals before trashing anything.


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## Rits (Dec 29, 2011)

Another easier method is open the terminal and type the following commands :

cp /System/Library/Extensions/IOUSBMassStorageClass.kext ~/backup/
sudo srm -rf /System/Library/Extensions/IOUSBMassStorageClass.kext
sudo touch /System/Library/Extensions
sudo reboot


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## sinclair_tm (Mar 11, 2005)

You should also be able to limit it with parental controls. But also remember, Macs are bootable from external devices, so if they boot from device, it won't matter the settings of your installed OS, and they;ll have free reign to get what they want from the computer. The best thing is to lock the iMac in a cabinet and control it via a secondary monitor and a keyboard and mouse on a long USB cable.


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## ash1111 (Mar 14, 2012)

Thank you for your help - you guys are brilliant ! - I think sinclair has full-proof security method.


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