How To Upgrade Ubuntu 10.04 (Lucid Lynx) To 10.10 (Maverick Meerkat) (Desktop & Server)

Start the Update Manager (System > Administration > Update Manager):

In the Update Manager, click on the Settings... button (in the lower left corner):

The Updates tab in the Software Sources window should open. Select Normal releases in the Show new distribution releases: drop-down menu and click on Close:

Back in the Update Manager, click on the Check button to check for new updates and distribution releases:

The Update Manager should show that a new distribution release (10.10) is available. Click on the Upgrade button to start the distribution upgrade:

A window with the release notes for 10.10 comes up. Click on Upgrade again:

The upgrade tool is now being downloaded. Afterwards, type in your password.
The upgrade is being prepared:

Click on Start Upgrade to finally begin with the upgrade process:

The upgrade packages are now being downloaded...

... and installed. This can take some time, so please be patient.

You might see the following message (Continue without installing GRUB?). I recommend to check the checkbox and click on Forward so that the system will continue to use the old, working GRUB. If you don't check the checkbox , the update manager will install a new GRUB and ask you on which device/partition it should be installed which can make the system unbootable if you select the wrong device/partition.

Because we had to change the Release upgrade settings in the Software Sources window, you will see the following message. It is ok to select Keep:

At the end of the upgrade process, you should remove obsolete packages:

The system needs to be rebooted to complete the upgrade, therefore click on Restart Now:

After the reboot, you can use your new Ubuntu 10.10 desktop:

 enjoyyyy........