In rare cases, a USB devices disconnects itself before VMware Fusion can recognize it.

When you plug in a USB device, the VMware Fusion EasyConnect dialog appears, but disappears before you have an opportunity to take an action. The USB device is then not visible to either your Mac or your virtual machine.

Some USB devices disconnect very quickly if they do not receive an immediate response upon connection. VMware Fusion USB EasyConnect can sometimes not produce a response in the time required by these USB devices.

To work around this problem you must set the virtual machine configuration file so that VMware Fusion connects unknown devices without having to ask first about the type of connection.


Power off or suspend the virtual machine.


Navigate to the Mac folder where the virtual machine is located.

The default location is /Users/your user name/Documents/Virtual Machines.


Right-click on the virtual machine package and select Show Package Contents.


Locate the virtual machine configuration file, virtual machine name.vmx, and open it with a text editor.


Add a line to the file to set how a USB device connects.



usb.generic.pluginAction = "guest"

Each time you plug in an unrecognized USB device, it connects to the virtual machine.

usb.generic.pluginAction = "host"

Each time you plug in an unrecognized USB device, it connects to the Mac.

usb.generic.pluginAction = "ask"

This is the default action, in which VMware Fusion uses the USB EasyConnect facility to present a dialog asking if you want to connect the device to the virtual machine or to the Mac. If you are experiencing the connection problem described in this troubleshooting topic, do not use this setting.


Save the file.


Power on or resume the virtual machine.

Plugging in a USB device results in it being connected to the virtual machine or Mac, depending on your setting, without going through the USB EasyConnect dialog. The device is also visible to the VMware Fusion interface, so you can see it in Settings > USB & Bluetooth.