Arena Tiny Window Fix

Did you get stuck with this tiny window when launching Arena?

Annoying Tiny Window

If so, the fix is quite simple. Follow the steps below.

Close Arena (or that tiny window)

Press the Windows key + R
Type in     regedit     then click OK

Press Windows Key + R, then type Regedit, and click OK

Navigate to: (screenshot below)
HKEY_CURRENT_USER/SOFTWARE/Wizards Of The Coast/MTGA/

Navigate to this location, then delete these 3 entries.

Delete the following items (Right-Click each one individually, select Delete)

• Screenmanager Is Fullscreen
  
• Screenmanager Resolution Height
  
• Screenmanager Resolution Width

Start Arena back up again, it should launch correctly this time.