Graphics driver stop working frequently

I have a DELL Inspiron 15.  Since I install Windows 10 anniversary update I have problems with the graphics driver.  I have an external monitor, connected through dock station. Sometimes when the computer start the external monitor freeze and the windows lock itself.  I have to disconnect the external monitor, disable the Intel HD Graphics 5500 and enable again. Normally this operation solve the problem.  Other times the computer start and works with the external monitor without problems.

I updated the driver on Dell website. I am using version 20.19.15.4463.   I also update Display link driver of my dock station but the problem continue.

Anybody have a suggestion to solve this problem?