Hide a running app from Dock?

Solution 1:

Important Note: In Mac OS X 10.5+ the method explained below only works for apps which are not using the "Code Signing" feature which was introduced in 10.5 to ensure authenticity of running code. The result of applying this method to a signed app differs; it might cause the app to crash upon starting or results it unexpected behavior.

You can edit the file Info.plist contained in the directory of each App (e.g. /Applications/VLC.app/Contents/Info.plist)by adding the following lines:

<key>LSUIElement</key>
<string>1</string>

For example:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
        <key>LSUIElement</key>
        <string>1</string>
        <key>BuildMachineOSBuild</key>
        <string>11G63</string>
        <key>CFBundleDevelopmentRegion</key> 
        ...
        ...
</dict>
</plist>

When you will start the App you will see the icon just for one second and the it will disappear.

Dockless and Dock Dodger do this change automatically in apps.

Solution 2:

1. This worked great. I wanted to open Mail every 15 minutes so I created a script in Applescript Editor that looks like this:

   repeat
   tell application "Mail"
   activate
   delay 60 * 15
   end tell
   end repeat

   The delay of 60 is 60 seconds and I multiplied it by 15 (=15 minutes)

2. Then in Applescript I clicked "Compile" then "Save" and named it "Mail Every 15" BUT made sure to name it as an Application not as a Script in my Applications folder.

3. Go to your Finder and in your Applications folder is your new file "Mail every 15". Right click that file and choose "Show package contents">Contents.
   You'll see a file named Info.plist in which you can open the file in your text editor by double clicking.

4. Once you open the file insert the code mentioned above and put just under the "dict" line

   Note: Once you start trying to edit it will warn you:

   You don’t have permission to write to the folder that the file “Info.plist” is in. You can duplicate this document and edit the duplicate. Only the duplicate will include your changes.

   Go ahead and duplicate it and make the 2 line change with the insert. Save the file to your desktop as Info.plist (just like the original file).

5. Your Finder should still be open, if not, reopen it by repeating step 3. Rename the original file, I named it Info-A.plist (just for safe measure. I'm sure you could just move the file to trash but I didn't want to take chances.)

6. I Swapped places with the files (Moved Info.plist from the desktop to the "Mail every 15>Contents" folder and moved the Info-A.plist to the desktop)

7. Go to System Preferences>User & Groups>Login Items and then I clicked on the + sign to add a login application to start it at boot up or login. Now it opens every 15 minutes and the Icon and App are no longer visible when it opens.

Hope this helps because I don't know anything about Macs and had to do a lot of research before I finally got it right. This web page was where I was at when I finally got it right so I'm logging this one for future reference.