To disable the creation of .ds_store files, launch the Terminal application from /Applications/Utilities/ and enter the following command string exactly:

defaults write com.apple.desktopservices DSDontWriteNetworkStores true

Reboot the Mac for changes to take full effect.

The login screen on your Mac is perfectly functional as it is, but if you want to spice it up a little bit, blogger Jacob Salmela shows you how to customize the login screen with a logo of your choosing.

If you don't want to install a whole program just for a simple tweak it's easy to do manually. All you need is a PNG that's 428 X 248. Then, you'll need to save it as four different files.

Here's instructions:

You need four copies of this file, and they need to be named:

• apple.png
• apple@2x.png
• apple_s1.png
• apple_s1@2x.png

Once they are named correctly, just drag them into the following path:

/System/Library/PrivateFrameworks/LoginUIKit.framework/Versions/A/Frameworks/LoginUICore.framework/Resources/

and then choose to replace all of them.

That's it, log out, and you should see your new logo. Head over to Salmela's site for a few sample images and instructions for making your own.

After I check the folder, I just know that the folder owned by “root” user.

ls -lah

sudo chown whoami .config

To disable the creation of .ds_store files, launch the Terminal application from /Applications/Utilities/ and enter the following command string exactly:

defaults write com.apple.desktopservices DSDontWriteNetworkStores true

First - open Finder -> Go to folder -> /Library/Caches

The second - find file com.apple.desktop.admin.png and replays it with your image ;) filename need be same = com.apple.desktop.admin.png. You also may rename jpg file to png without converting.

Open Terminal and enter the following in a single line:

/System/Library/CoreServices/Menu\ Extras/User.menu/Contents/Resources/CGSession -suspend

Launch the Terminal, you'll see a list of all your messages. From the mail prompt, do

$ mail
? delete *
? q

And that should be it. Make sure do to the q after the delete * command, that saves the changes to disk.