Type: Answers

Area: Tools

Why is my USB Blaster II not detected by Quartus II on Windows?


The USB-Blaster™ II  may not be detected if there is a conflict between the USB-Blaster II driver and other 3rd party drivers on your PC.

If your USB-Blaster II is not detected when running jtagconfig from the command line, you should inspect the Windows Device Manager. 

If there is a conflict with a different USB driver:

  •  The Altera® USB-Blaster II (Unconfigured) device is shown with a warning symbol in the Windows Device Manager
  • The device status pane of the properties window for the Altera USB-Blaster II (Unconfigured) device displays (Code 38).


To resolve this problem, the USB device that is in conflict with the USB-Blaster II should be unplugged. 

Many computers also use USB to communicate with built-in peripherals such as SD card readers.  These devices may be disabled using the Windows Device Manager.

This problem is scheduled to be resolved in a future release of the Quartus® II software.