Permissions trouble with new MacBook Pro

Question

I had previously upgraded my MacBook Pro (original unibody model) to Mountain Lion with no apparent issues. I have two Users, both with Admin status and everything appeared to function as before.
I just traded in my old MacBook Pro for a new current model Retina MacBook Pro, using Migration Assistant upon first startup to move everything over from the older machine. Most everything has been seamless - except for Permissions.
I started seeing messages appear indicating I didn't have permission to open files, run apps, delete files, etc. Looking at Get Info, I found Sharing & Permissions was only set up for (if I recall correctly) Admin, Administrator and something called Wheel. I solved the permissions issue while logged in as the primary User by adding both Users to the Sharing & Permissions section of the Info screen for the entire hard drive, giving them Read & Write access, and selecting Apply to enclosed items... That seems to have solved the issue for the primary User.
But then I tried working logged in as the secondary User. I started getting messages indicating I could not save a file I had just modified because I did not have permission, and that I should contact the Administrator. Well, that's me. So I tried the same thing that I did logged in as the primary User, but there was no change. I still can't save a modified file logged in as the secondary Admin User.
I haven't found anything that addresses this - except to learn where the Wheel User originated. Can someone point me in the right direction to where I can learn how to gain full, unlimited access to my own computer - under bothe User accounts?
Thank you.

Answer 1

You corrupted the permissions of every file on the volume. Restore everything from the backup you made before doing that. Then do as follows.
Back up all data. Don't continue unless you're sure you can restore from a backup, even if you're unable to log in.
This procedure will unlock all your user files (not system files) and reset their ownership and access-control lists to the default. If you've set special values for those attributes on any of your files, they will be reverted. In that case, either stop here, or be prepared to recreate the settings if necessary. Do so only after verifying that those settings didn't cause the problem. If none of this is meaningful to you, you don't need to worry about it.
Step 1
If you have more than one user account, and the one in question is not an administrator account, then temporarily promote it to administrator status in the Users & Groups preference pane. To do that, unlock the preference pane using the credentials of an administrator, check the box marked Allow user to administer this computer, then reboot. You can demote the problem account back to standard status when this step has been completed.
Triple-click the following line on this page to select it. Copy the selected text to the Clipboard (command-C):
{ sudo chflags -R nouchg,nouappnd ~ $TMPDIR.. ; sudo chown -R $UID:staff ~ $_ ; sudo chmod -R u+rwX ~ $_ ; chmod -R -N ~ $_ ; } 2> /dev/null
Launch the Terminal application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.
Paste into the Terminal window (command-V). You'll be prompted for your login password. Nothing will be displayed when you type it. You may get a one-time warning to be careful. If you don’t have a login password, you’ll need to set one before you can run the command. If you see a message that your username "is not in the sudoers file," then you're not logged in as an administrator.
The command will take a noticeable amount of time to run. Wait for a new line ending in a dollar sign (“$”) to appear, then quit Terminal.
Step 2 (optional)
Take this step only if you have trouble with Step 1 or if it doesn't solve the problem.
Boot into Recovery. When the OS X Utilities screen appears, select
Utilities ▹ Terminal
from the menu bar. A Terminal window will open.
In the Terminal window, type this:
res
Press the tab key. The partial command you typed will automatically be completed to this:
resetpassword
Press return. A Reset Password window will open. You’re not  going to reset a password.
Select your boot volume ("Macintosh HD," unless you gave it a different name) if not already selected.
Select your username from the menu labeled Select the user account if not already selected.
Under Reset Home Directory Permissions and ACLs, click the Reset button.
Select
 ▹ Restart
from the menu bar.