this means you haven’t installed sketchup. what you’re seeing is the disk image you downloaded and opened.
see the “sketchup 2026” folder ? drag it on to the “applications” shortcut.
then eject it and delete the disk image.
this is what the disk image looks like when you’re not looking at it in list mode :
until you do that, yes sketchup will launch, but from the disk image, meaning it won’t save some of your preferences, it’ll be slower, might be unstable…