SymptomsThe "USB device you are trying to connect to the virtual machine is being used by another process" error message appears when you attempt to connect the device.
CauseAny operating system requires its own exclusive access to the device in order to be able to use it. The same device can't be connected simultaneously to two operating systems (Primary OS and Guest OS in the VM).
- If you have Parallels vesrion 2.5 installed, upgrade Parallels version 2.5 to the 3224 build (version 2.5) via the "Check for updates..." menu option from the "Help" menu.
- Reinstall Parallels Tools via the "Actions" menu.
- Install all required device drivers.
- Select the USB device via "Paralells" - "Devices" menu.
In case of Parallels Desktop 3.0 please try one of the solutions below:
A.Open Configuration Editor - USB Controller and check if it is set to Connect to Guest OS by default. Launch Windows, go to Devices -> USB in Parallels Desktop menu bar and try disconnecting - connecting again the device. Do not connect the device to the computer until you start Windows.
B.In Configuration Editor - USB Controller choose Connect to Mac OS X as Connection Option. When you launch Windows enable the device through Devices - USB in Parallels Desktop menu bar.
C.If the device worked properly before updating to 5580, try a custom build with improved USB device implementation.