Locate the The Elder Scrolls Online game file. This file can normally be found in C:Program Files (x86)Zenimax OnlineThe Elder Scrolls Online Betagameclienteso.exe. It is important to note that this is NOT the launcher, but the game file for the Beta itself.
Once that file is located, right-click the file and select Properties at the bottom of the list.
Once the Properties window is open, select the Compatibility tab.
Select the option to “Run this program in compatibility mode” and from the drop-down menu select “Windows XP SP3” (it may say Service Pack 3).
Select the option “Always run this program as an Administrator”
For ease of use, right-click the eso.exe file and select “Send To…”
From the subsequent slide-out menu, select “Desktop (Create Shortcut)”.
This will allow a very easy, quick way of opening a game running in compatibility mode.

Let me know if it helps.