how do i install ichat back on my mac

Have you checked in the Applications folder and used Spotlight to search for it just in case it was accidentally moved? If it has just been removed from the Dock but is in the Applications folder, then drag the icon back into the Dock.

If it is truly gone then reinstall OS X if you are using Lion. If Snow Leopard or earlier then the following:

How Restore Deleted or Missing OS X Components

A few of the basic OS X installed applications can be restored from the Optional Installs installer located in the Optional installs folder on your Installer DVD. However, if what you need is not there then follow the instructions below.

How to Use Pacifist to Restore Deleted or Missing OS X Components

Insert the OS X Installer DVD into the optical drive. Use a simple utility like TinkerTool to toggle invisibility so you can see invisible items. Alternatively, open the Terminal application in your Utilities folder and at the prompt enter the following:

defaults write com.apple.finder AppleShowAllFiles Yes

Press RETURN.

To turn off the display of invisible files repeat the above command substituting No for Yes.

The install packages are located in the /System/Installation/ folder on the DVD.

Download the shareware utility Pacifist. Use it to extract a fresh copy of the missing item(s) from the file archives on your OS X installation DVD. The file archives are in the /System/Installations/ folder (use Go to Folder option in the Go menu of the Finder.)

Here are Four Basic ways to use Pacifist (courtesy of George Orville.)

1. Drag a .pkg icon onto the Pacifist window .....proceed to step 7.
2. Click on “Open Package ....” and navigate to package desired and click “Open” in the open/save window.....proceed to step 7.
3. Insert Mac OS X installer CD and when it mounts, navigate to .... Menu->Go->Go to Folder. In the path field enter or paste ....

/Volumes/disc name/System/Installation/Packages (where disc name is the name of the CD/DVD that you inserted.)

Click on the "Go" button ..... • Drag a .pkg to Pacifist..... proceed to step 7.

The package you'll need will have to be discovered by trial and error, but for most applications you should start with the Essentials.pkg and/or Additional Essentials.pkg.

D. Insert your Mac OS X install disk 1 .... and open Pacifist.

1. In Pacifist, select "Open Mac OS X Install Packages" ... dialog may appear asking for disk 2, then disk 3 and finally disk 1 again.... {if DVD is not used)...If “Stop Loading” is selected...the procedure will stop!!!

2a. When loading is complete, a new window appears, click the triangle to display contents of each package...Select item and proceed to step 7.

2b. or click the “Find” icon in the Pacifist window and type the name of the software you need.

3. In the list that comes back, click the top most entry for the item that you want. ..... that is the one for the English language.

4. On the top of the Pacifist window, click “verify” .... you will probably be prompted for your password.

5. Enter checks for.... “verify permissions” and “verify file contents.” and click “verify” ....enter password when prompted.... you will get back output which may look like this:

20 files were scanned. 20 of 20 files were present on the hard disk. 0 of 20 files had file permissions that did not match those specified in the package. 0 of 20 files had checksums that did not match those specified in the package.

6. Click “close”. Go to step 7.

Extract or Install........

7. In the Toolbar (upper left), you now have the option to extract or install. Click a file in the lower list and those two icons will be enabled.

8. If “Extract to...” is selected.... navigate to the location where the file will be placed, select “choose”, select “extract” in new dialog that appears,authenicate , if prompted, click “OK”.

9. In the next dialog, click “Extract”.

10. If “Install” is selected... dialog will appear with the location/path of the installed software. Click “Install”

11. Type in your password, click “OK”

Pacifist will begin to extract files.

12. In steps 8/10ß.... you also have the choice to “cancel”

Notes: Pacifist may find that a file it is installing already exists on the hard disk. Pacifist will present you with an alert panel....

• Stop
• Leave original alone
• Update .....
• Default selection
• Replace .... (Replace option should only be used on full install packages)

https://discussions.apple.com/thread/1486891?threadID=1486891

HI all,

Reinstalling iChat this way requires that you make sure it gets Updated to "Match" the OS.

Your Install Disk is likely to be at least several OS updates behind your current set up.

iChat gets Updates in the OS Updates (Not everyone but enough to make a difference)

Having reinstalled ichat it is important to Download and Install the COMBO Version of the Last OS Update you did.

Even if you use the "Easy way" listed in the specific User Tip (listed by Defcom) you will still need to do the Combo Update to update iChat.

9:20 PM Monday; February 27, 2012

Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"

 iMac 2.5Ghz 5i 2011 (Lion 10.7.3)
 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb (Snow Leopard 10.6.8)
 Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images."  No, Seriously