GRAN TURISMO 6 (GT6) = Version 1.22 Update / Installation Error = Fixed

*Make sure your Disc Auto-Start is set to Off:
Settings/System Settings/Disc Auto-Start/Off
* Make sure your disc is clean!
Remove Disc and wipe with a dry, lint-free cloth.

From XMB:
1. Settings/Network Settings/Internet Connection/Enabled
2. PlayStation Network/Sign In
3. Insert Disc.
4. Game/GT6/*Triangle* for Options/Check For Update.
5. Press OK. The update will start to download within the XMB.
6. Download the first 6 updates only.
7. Allow the updates to install, but cancel the 7th update and exit.
8. Remove Disc.
9. Disconnect the internet.
10. Insert disc.
11. Start GT6 and cancel the connection prompt.

The updates will now install within GT6.

This part is important:
After playing around a bit inside GT6 offline, press Start and select Options:
1. Game Data/Install Game Data/Delete Installed Files.
2. Network/Clear System Cache.
3. Exit and manually Save
4. Quit game.

From XMB:
1. Game/GT6/Remove disc.
2. Settings/Network Settings/Internet Connection/Enabled
3. PlayStation Network/Sign In
4. Insert Disc.
5. GT6/Options/Check For Update.
6. Press OK. The 7th update will start to download.
7. Download the first update only.
8. Allow the update to install, but cancel the next download and exit.
9. Remove Disc.
10. Disconnect the internet.
11. Insert disc.
12. Start GT6 and cancel the connection prompt.

The update will now install within GT6... Again.

Repeat the last 12 steps above until you're at the latest version 1.22.

Be patient, and follow every step, every time. ie. Remove disc, Clear System Cache and Delete Installed Files. It may be a random thing, but worked for me this time.

All I can say is GOOD LUCK!!