Our small company uses Google Drive to store some medium-sensitivity documents (they should not contain highly personal information, but still things that would be embarassing to leak and potentially benefit our competitors). Storing them in Drive has been a very convenient solution in our situation, and our employees would be resistant to moving away from it. Most people have installed the google drive desktop app, that syncs the Drive files to their own machine, and they like this feature too.
What I'm concerned about is a scenario where our employee's laptop would be lost or stolen, and the thief would access the hard drive, and thus these Google Drive synced files. What are my options to protect against this scenario? I would like to interfere with our employees' processes as little as possible, so I would appreciate the most convenient, but still secure solution. Some kind of encryption of files, folders or entire hard drive would probably be required, or is there another way? How could I enforce this on all users without too much extra work for them?