Customizing Mac OS X's login window for your organization

In my years as a systems administrator for higher education, I always modified the login window environment of Mac OS X for each computer lab that I managed. I did this for a couple of reasons. One was to give the computing environment a sense of school spirit with a custom background graphic reflecting the program or department of the lab or classroom as well as the school. It also made it easy to identify if a computer had been moved from one lab or department to another and to identify whether the computer had booted from its internal hard drive without logging in. But, the most valuable reason was to put any instructions and acceptable use policies front and center so that no user could claim not to have seen them. Although it might seem like a lot of work to do this, changing the login window in these ways is actually very simple to do either manually or with the shareware tool Visage. If you use disk image-based deployment methods (NetInstall, Apple Software Restore, etc.), you can simply make the changes to the machine from which you create your image. If you want to make changes later, you can use Apple Remote Desktop to easily push those changes out to large number of computers at once. To change the background image of the login window manually, create the image that you want to use, save it as a JPEG, name it "Aqua Blue.jpg" (the name of the default file), and place it in Macintosh HD/Library/Desktop Pictures (changing the hard drive name if needed). To push this file out to a number of computers, you can use Apple Remote Desktop's Copy Files feature to place your image appropriately across multiple computers in one step. Note: this image will also become the default desktop picture for new users. To manually add a login banner message, you need to edit the com.apple.loginwindow.plist file. You'll need to do this using the command line because only root has the ability to make changes to this file. Simply enter the following (replacing the asterisks with your message): $ sudo defaults write /Library/Preferences/com.apple.loginwindow LoginwindowText "******" You can remotely add or change the login banner on a large number of Macs simultaneously by using the Send Unix Command feature in Apple Remote Desktop.