Hi Veerle Maris,
The issue that you are facing usually occurs due to GPU drivers. You may refer to this post and update the drivers accordingly.
Also, if updating the drivers is not helping you may try switching the renderer to Mercury Playback Engine Software Only.
You may refer to this link to learn more about switching renderers to solve the preview issue.
Hope you find it useful, you may let us know if this helped.
Sumeet Kumar Choubey