<p>See forum thread -&nbsp;<a href="https://forum.team-mediaportal.com/threads/direct3d-device-could-not-be-created-prohibiting-mp-start.137632/">https://forum.team-mediaportal.com/threads/direct3d-device-could-not-be-created-prohibiting-mp-start.137632/&lt;/a&gt;&nbsp;&lt;/p>

<p>Invalid values in&nbsp;MediaPortal.xml for 'backupsizewidth' and 'backupsizeheight' can cause the 'CreateDeviceEx' call in CreateDirectX9ExDevice() (in D3D.cs) to fail, which will prevent MP1 client from starting in 'windowed' mode.</p>

<p>To reproduce, edit&nbsp;MediaPortal.xml so that&nbsp;&nbsp;'backupsizewidth' or 'backupsizeheight' is zero then start MP in windowed (not fullscreen) mode.</p>

<p>FIx is to add sanity/bounds checking of these values before they are written (on MP close) and when they are read at startup, and replacing them with sensible values if necessary.</p>