USB device you are trying to connect to the virtual machine is being used...

Hi

I get the dreaded USB error when trying to connect a usbtiny avr programmer. I'm using Leopard 10.5.5 and Parallels build 5608.

Unfortunately, the solutions suggested in the knowledge base (make sure that "connect to guest os by default" etc.) do not make a difference. The device itself can hardly be faulty as it works perfectly with native pcs.

What's the solution if the above mentioned knowledge base solutions do not work? I tried everything I can think of and am going nuts.

Martin

 

Hello,

The problem is most probably due to the fact that MacOS recognizes such devices as USB storage devices and loads a kernel extension which blocks the device.
Please note that it is either a MacOS or a USB device limitation, so if the below advice does not work, you should also try addressing the problem to the corresponding manufacturer.

So, please, try the following suggestions:
- check your device manual and turn it to normal mode if it has a normal/storage modes switch
- unplug _all_ USB devices from your Mac (otherwise they will be switched off automatically and it could lead to the data loss).
- open Terminal application (Finder -> Applications -> Utilities)
- issue the following command:

sudo kextunload /System/Library/Extensions/IOUSBMassStorageClass.kext/

 

On the one hand I only get a "failed" message when I issue this command, on the other hand would this mean that no external hard drives could be used any more? This would, of course, be no solution then.

Regards
Martin

 

No, it means that Mac OS cannot release device , you can check it also on Mac without Parallels Desktop, somehow Mac thinks that he has driver, but it doesn't and thus tried to load device still and cannot release