android studio3 sdk,Android SDK missing with Android Studio 3

try to reinstall it and download(automatically downloaded) the required file after restart, but follow the steps

1 go to your main drive(consider 'c') then c/user//androidstudioproject and copy it to some other location(save your old

projects to safe location)

2 uninstall android studio from control panel

3 delete following file

a c/user//androidstudioproject

b c/user//.android

c 'c/user//AppData/Local/Android (keep hidden files on)'

4 now install your androidstudio from its setup

these will automatically download the required files after installation (always connect to internet while installing)