A few people have reported that when using the latest version of iTunes in OS X 10.6.7 they experience errors in which the program immediately crashes when launched. When this happens, the program displays a message that states, "You do not have enough access privileges for this operation" and then quits followed by the OS X crash reporter.
As with most application crashes, people experiencing this problem have tried numerous approaches, including running in Safe Mode, removing the iTunes preferences files, loading a new user account, and deleting system caches with various maintenance programs; however, in this situation none of these efforts helps.
This particular problem happens when iTunes cannot access the Shared folder, which should be located alongside the user home folders in the /Users directory. iTunes creates a hidden folder in this directory called "SC Info," which needs to be accessible by all users in order for iTunes Store authorizations to work properly. In some situations people may find that the entire Shared folder is missing, but in other situations the permissions for this folder may be set incorrectly.
In a knowledgebase article that addresses authorization problems in iTunes, Apple outlined the proper permissions setup for this folder, and people experiencing the "access privileges" crash have found that resetting these permissions or in some cases re-creating the missing Shared folder has fixed the issue.
To do this, first check to see if the /Macintosh HD/Users/Shared/ folder exists on your system, and if not, then create it by running the following command in the Terminal utility (located in the /Applications/Utilities/ folder):
sudo mkdir -p /Users/Shared
This command should create the directory so it is owned by the root user and that all users are given full read and write access; however, double-check the ownership and permissions for the directory by getting information on it in the Finder and looking at the Sharing & Permissions section. You should see "system," "wheel," and "everyone" in the left column, followed by "Read & Write" in the right column for all entries. If this is not the case, then run the following command:
sudo chown root:wheel /Users/Shared
This command will change the owner of the directory to "root", and the group to "wheel" (the group of users that can run the "sudo" command--primarily administrators).
Once the ownership is set up and confirmed for this directory, then run the following command (for OS X 10.6 users) to set the permissions on the folder and all enclosed items so everyone has read and write permissions:
sudo chmod -R 1777 /Users/Shared
If you are using OS X 10.5.x or earlier, run the following command:
sudo chmod -R 777 /Users/Shared
The difference here is the first command enables the "sticky bit" for the Shared directory; it is a system limitation that only allows the directory's owner or the root user to remove or rename files. This is not necessarily needed but should restrict items in the Shared folder from being inadvertently removed or changed by other users on the system, while still allowing existing files to be read from and written to. This is generally a good option to use for resources on the system that are shared between two accounts.
The reason for using the sticky bit only in Snow Leopard systems is unclear, as the behavior of this setting should be the same in both OS versions (and in testing they appear to work similarly); however, Apple's knowledgebase article specifically mentions using one for Leopard and the other for Snow Leopard.
After this is done, relaunch iTunes, and the program should now load and function properly again.
Note: The commands here use "sudo" before them, which will run the commands with root privileges and therefore will need to be run from an administrator account. Running as an administrator can be done by directly logging into the administrator account to run these commands, or you can type "su ADMIN" (where ADMIN is the an administrator account's short username) in the Terminal from within a standard user account, followed by the admin account's password. This will "switch users" to the admin account for the current Terminal session, and then allow you to run the "sudo" commands.