1 Install Android USB Driver

To install the Android USB driver on Windows 7 for the first time:

1. Connect your Android-powered device to your computer’s USB port.
2. Right-click on Computer from your desktop or Windows Explorer, and select Manage.
3. Select Devices in the left pane.
4. Locate and expand Other device in the right pane.
5. Right-click the device name (such as Nexus S) and select Update Driver Software. This will launch the Hardware Update Wizard.
6. Select Browse my computer for driver software and click Next.
7. Click Browse and locate the USB driver folder. (The Google USB Driver is located in <sdk>\extras\google\usb_driver\.)
8. Click Next to install the driver.

Alternately, to upgrade an existing Android USB driver on Windows 7 with the new driver:

1. Connect your Android-powered device to your computer’s USB port.
2. Right-click on Computer from your desktop or Windows Explorer, and select Manage.
3. Select Device Manager in the left pane of the Computer Management window.
4. Locate and expand Android Phone in the right pane.
5. Right-click Android Composite ADB Interface and select Update Driver. This will launch the Hardware Update Wizard.
6. Select Install from a list or specific location and click Next.
7. Select Search for the best driver in these locations; un-check Search removable media; and check Include this location in the search.
8. Click Browse and locate the USB driver folder. (The Google USB Driver is located in <sdk>\extras\google\usb_driver\.)
9. Click Next to upgrade the driver.

2 Download Rooting software

1. You can download the software from the chainfire site: http://autoroot.chainfire.eu/.
2. Look for nexus 6 and click on Download button.
   
3. Unzip the download file and the content will look like this:

3 Root the Device

1. Turn off the device and then turn back on by holding Volume Down and pressing Power button.
2. Connect the device with the USB. It should say USB Connected.
   
3. Double click on root-windows.bat and let it unlock and then root the device.
4. The device will reboot after about a minute and the device will have been rooted.

 

4 Confirm that the Device is rooted

To confirm that the device has been rooted correctly, the easiest way is to download a Root Checker app. After installing, click on the CHECK button and the Root Access will says access granted.