Google Drive will tell you who has access to your files

Google is introducing an updated Access Checker, a feature which lets you easily share a Drive file with someone, whether it’s two colleagues or a team of 30. The feature alerts you when you send an email, calendar invite, or another type of note that includes a Drive file, and will ask you if you want to change permission settings if the recipient doesn’t yet have access. When you’re emailing the file to various recipients, Access Checker will now also show you the names or email addresses that don’t currently have access to the file.