I understand you would like to know the maximum amount of monitors you can connect to your Acer Aspire E17 E5-773-579L laptop.
Let me apologize for any inconvenience this issue may be causing to you.
Our graphics controller (Intel® HD Graphics 520) supports up to three displays simultaneously.
I checked the specifications of the laptop and found out it comes with one HDMI port only. Your computer was most likely designed to support up to two displays (built-in display + HDMI display). You can try checking with Acer* directly if there is or not a way to make the computer work with more than two monitors. This link will give you their contact information https://www.acer.com/ac/en/GB/content/service-contact
I have just read the answer you gave to this customer.
I have a DELL LATITUDE 5270. It has Intel HD520. I have a Samsung monitor which only has VGA and DVI ports (but does not have HDMI port) and a TV which has either VGA and HDMI ports.
I connected the Samsung monitor by using a VGA to VGA cable, since my Dell Laptop has VGA connector.
I also connected the TV to the HDMI port. I wanted to have these two monitors in extended desktop (besides the laptop monitor, so three in total).
The TV did not worked. The Samsung monitor worked.
So I disconnected the Samsung monitor and I left only the TV connected through HDMI. And it worked.
So it looks like I cannot have three monitors when one is VGA and the second one is HDMI.
My question is: how can I do to make it work? If I use a VGA to HDMI adapter for the Monitor and I also use a USB docking station where I plug both the monitor and the TV with HDMI, will it work in extended mode?
Are there USB docking stations which has VGA and HDMI? Would it be good in this case?
I will be looking forward for your answer.
What happens is that the graphics controller that comes on Intel HD Graphics 520 does not natively support VGA. Implementation of the VGA port is done by the computer manufacturer directly through a 3rd party chip. We cannot guarantee 3-Display feature will work fine with that 3rd part adapter.
What I can recommend is contacting Dell* directly in order to check if there is or not a way to have 3-Display configuration with the setup your computer currently has. This link will give you their contact information http://www.dell.com/support/incidents-online/us/en/04/contactus/Dynamic