I discovered a trick for that problem.
On HLK Studio, go to Configuration -> the machine pool selected for your project.
Select the machine where you cannot find your driver.
Right-click on it and click on Delete Machine.
Go to the Default Pool.
Select the same machine and drag it again until the previous pool.
Maybe then you will find your driver there.
It works for me.
If not, you may also try to click on the other groups: systems, devices and printers, etc.