This tip outlines the few steps required to repair the disk permissions. 

A process that should be performed before any updating the system.

Why should I repair disk permissions? Third-party software installers, applications that temporarily change, but fail to reset, permissions on System-related files or folders during a software installation, are a primary cause of permissions-related problems. Accordingly, you should run Repair Disk Permissions after installing any third-party software that employs its own installer. In addition it is good practice to run Repair Disk Permissionsbefore updating OS X as we have now all learned from the 10.5.1 to 10.5.2 and 10.5.2 to 10.5.3 debacle.

Tun run Repair Disk Permissions open a Finder window by clicking on the Finder icon in the Dock, selecting from the Finder’s File menu New Finder Window, or by pressing the Apple + N keys.

The Finder window will open displaying your home folder content. Click on the Applications icon in the left side in the Finder window under the Places section:

Note: My Finder preference is to use the List view to display files and folders. You may be useing another view option.

The Applications folder content will be displayed. Scroll down the window unbtil you see the Utilities folder. Double-click on the Utility folder icon:

The Utilities’ folder content will now be displayed. Double click on the Disk Utility icon to start up the application:

The Disk Utility application will now start up and display the window below showing your systems connected storage devices. Select your system drive (the one your system used to boot and where the OS is installed on) by clicking on it. In our example it is the 74.5 GB internal hard drive which contains the Macintosh HD partition.

The main window content will change to show the First Aid pane. Click on the Repair Disk Permission button to start the process.

Note: There is a button labeled Verify Disk Permissions, my option is that Apple should remove it since the time it takes to tell you there is a need to repair the disk permission you could have run the repair instead. There is no harm done in running the repair right away instead of the verify process.

The window will now display within its status window that the process has started. A progress bar will display much more needs to be checked. I have found that the estimated time is actually misleading as it always starts of with less than 1 minute and as time progresses it will change to some more realistic estimate. Be prepared that depending on the disk size and files and folder count this may take some time.

The status window will show if any permissions problems are found that it will repair:

When completed the status window will report that the Permissions repair is complete. You may see messages about ACL found but not expected on “……”, you can safely ignore these messages as per Apple. You can close the Disk Utility by clicking on the red circle (bubble) in the top-left corner of the disk utility window or selecting Quit Disk Utility from the Disk Utility Menu.

Note: Personally, I run the Repair again if it found anything to repair to make sure that the problem was actually resolved. I have run it to a problem where the repair did not work and I actually had to run Repair Disk which is more complicated as you have to start from anther disk to repair the system disk. But that is for another Hints entry.