The tool should show your device as "Connected" on one of the COM ports. button at the top left.
: If it shows as "Unknown Device" or "QHUSB_BULK," right-click it in Device Manager, select Update Driver , and manually point to the extracted driver folder.
For unbricking a OnePlus 3T , the primary tool used is the MSM Download Tool
Are you currently seeing any in the MSM tool or is the device not showing up in Device Manager at all? [OnePlus 3 & 3T] Returning to Stock and Unbrick Process
Now that the phone is recognized, let’s bring it back to life.