When you uninstalled an old installation, did you also remove your account/the Insync’s database first? If not, it would have tried to pick up from where it left after re-installation. Did it complain about the missing folder and then you redirected it to your Google Drive folder?
You should have first removed the account and then set it up again at the Google Drive folder. Please send to us the Insync logs at support@insynchq.com