Blender is rendering an older version of my project, not the most recent one. I have made it using the Blender Render but it does not want to render in cycles either. A black and grey screen is rendered as if everything is transparent. Checked general camera, lighting and compute devises in case I messed something up but I can't find anything. All my textures and objects look normal, does anybody know what is wrong or what to check?
This is because you have some sequencer strips in the VSE.
The Compositor and Sequence settings are enabled by default, so if there is any data in the compositor or the sequencer blender will render from that instead of the scene.
From the wiki:
Disable Sequence in Render Settings > Post processing or remove the sequencer strips and it will render the scene instead: