I have the same problem since I started working with Xcode in october. Reported the issue several times, but no reaction in the feedback app.

Hi, I am just a beginner. Currently I have only issues with the preview. I could not find the option to change the sim runtime of the preview. The only option is to change the target of simulator, not preview. I used the button to change target in top bar and below the preview. But all versions produce the same error. I have 18.6, 26.0 and 26.1 installed. If I remove 26.1, then the preview complains about missing runtime and I get a download button to install 26.1. Reinstalling 26.1 does not solve the issue.

@Developer Tools Engineer The versions 18.6, 26.0 and 26.1 seem to have the issue. What can I do now?