I, user X:
1) Want to add encryption security to certain files.
2)don’t want to (’cause it’s a pain in the arse, or for some practical reason can’t) use a lock screen.
3) know what this means. I also know the extent and limitations of the added security the requested functionality provides.
End result of user described above with the option of using the requested functionality: Greater security.
Given the stated aims and expertise of some the contributers here, Im not sure why Im the only one pointing this out here (reiterating even) but a screen saver password /screen lock is NOT in and of itself sufficient to stop someone with physical access to your drive from taking operating on data held on it. It requires additional security measure such as (in the case of Windows ) EFS encryption of the files on the drive – a feature not turned on by default (or even supported) in some versions of windows: