i was about to export my file to 2D dwg file but it always says like the picture i attach, but i wasn’t open any file beside this
This is in SketchUp for Schools as your profile says you are using? That’s a web based version for school children.
Share the .skp file with us.
im confused, i used the sketchup for college purpose thats why i wrote it school. its misunderstanding i guess.
any idea why the app says like that?
A college wouldn’t have SketchUp for Schools. They might have an education lices for SketchUp Pro but it’s still SketchUp Pro.
It’s hard to say. Close SketchUp and reopen it. Then try again.
i did that earlier! i even restart the laptop but it doesnt work 
Share the SketchUp file as I asked you to do in my first reply.
2024131.skp (191.7 KB)
Looks like there’s some process running on the computer. I had no trouble exporting a .dwg from your model on my computer.
2024131.dwg (4.6 KB)
Is this on a school computer or your personal computer? Maybe you need to find an IT person to help you out.
Its a personal laptop actually, anyway thankyou for helping! means a lot to me 
Are you saving the model to a folder that is automatically synced to the cloud, or directly to a cloud service? This might happen if a sync is in progress when you try to save.
i dont think so, i save it regularly
also turns out i cant do import dwg too, any idea?