If you have ever tried to open a drawing only to find that it is already open so that your only option is to open a read-only copy then this tip is for you. Starting in AutoCAD 2004 the WHOHAS option was enabled by default. You may have noticed .dwl files being created in the folder along with your drawings and wondered why they were there, this is also part of the WHOHAS option. When a drawing is opened the .dwl (Drawing Lock file) is created. This temporary file stores the user name and computer name of the person that opened the drawing as well as the time that the drawing was opened. While you are in AutoCAD you can type WHOHAS at the command line and then browse to select a drawing. If the drawing is open you will see a dialog box that tells you who has the drawing open and what time it was opened. Now that you know who has your drawing you still need to gain access the old fashioned way, by asking the person if they are finished and coordinating when you can use the file. I guess that AutoCAD can only do so much for us and we still might have to talk to our coworkers. But at least the WHOHAS command will tell you who you need to talk to.