I opened a file and began editing. My co-worker opened the same file but did not receive any kind of warning that someone else had it opened so he began editing. He saved his work and closed the file. Then I finished, saved and closed the file. We use file versioning but no version of his work is available. We have tested this out and when two people are editing a file at the same time only the version which is saved last actually shows up. We loose all the work done by the second employee. Is there some way to get a warning when an employee opens a file that is already currently open by someone else?