I'm planning to upgrade my OS from 10.04 LTS to 12.04 LTS using the Update Manager as a source. This is the first time doing this. Thus, I have some questions.
Is this a fairly safe way(using Update Manager) to do it?
What happens to the data that I have in my home folder?
What happens to the applications that I have installed?
My desktop GUI is Macbuntu. I suppose it will be erased. Is that so?
My mail application is Evolution. I use local folders within the mail app to save important emails. What would happen to my email data, since I know that the default mail app in 12.04 is Thunderbird?
What other considerations I should take into account before doing this upgrade?

Thanks for your advice.

Hi, first, read here:
https://help.ubuntu.com/community/UpgradeNotes
https://help.ubuntu.com/community/PreciseUpgrades
https://wiki.ubuntu.com/PrecisePango.../UbuntuDesktop

Now that you have self-educated, you are prepared to proceed with confidence.

I highly recommend that you back up all data before proceeding, in fact the best choice in my opinion is to back up the entire partition using a program such as Clonezilla so that you can easily restore your system to its current working state if something goes wrong. If it is a production/mission-critical machine, then I recommend you go 2 steps further and: 1) practice the upgrade on a spare machine first; and/or 2) install 12.04 side by side with 10.04 as a "dual boot" so that you can transition between the two at your own pace, with 10.04 as a working fallback until you are confident 12.04 is set up the way you need.

Of course, many Ubuntu users upgrade without taking these precautions. Some of them even succeed! Suggest you read other users' experiences here:

http://ubuntuforums.org/forumdisplay.php?f=333
http://ubuntuforums.org/forumdisplay.php?f=103

Also I hope you are aware that the user interface has changed radically, if this is news to you then burn and test-drive a Live CD of 12.04 to see if you even like it.

@snowpine:

Thanks for the abundant data for my education you've provided related to this upgrade. I'm going to go through it very shortly. I just wanted to say thanks first. Installing 12.04 from a live CD, I have experience, doing a clean install on an empty hard disk. I'm also familiar with the Unity desktop, etc. What is new to me is doing an upgrade from within the Update Manager. Never done it before. Additionaly, my Ubuntu 10.04 OS is on an external USB drive, dual booting from a Windows XP machine. And it has been working fine for the past three years. I'm doing this because I was informed that 10.04 LTS has less than 6 months support cycle.

I used the Update Manager to upgrade from 10.10 to 11.04 and subsequently to 11.10. Obviously that would include considerably fewer changes than 10.04 to 12.04. I don't recall any problems but it was a very basic system with very little additional software as I use Ubuntu infrequently. It has been a while since I have done this but I beleive I forgot to run sudo update-grub before rebooting and was unable to boot. That and the backup and other suggestions above will hopefully minimize problems.

Is your home folder on a separate home partition? Or do you just have one root partition with the home folder on that root partition?
If you have a separate home partition, your data will be safe during an upgrade. Your data will also be safe if you do a clean install of 12.04 as long as you choose manual partitioning and choose not to format the home partition.

I use a separate home partition. I always do clean installs of Ubuntu since it is the most trouble free method for doing an upgrade. My data has always been safe using this method.
If you do not have a separate home partition, then if you ever reinstall Ubuntu I would strongly suggest choosing manual partitioning during the install and create a separate home partition for your data.

I would like to add to this recommendation. If you use UM to do a version upgrade and it, for some reason, goes bad this will most likely save your data.

The LTS to LTS upgrade is well tested during the testing cycle for the new LTS. That is to say it was well tested during the 12.04-testing cycle. It should be pretty safe at this point.

Doing a clean install on a 2 partition system is usually a better choice. This is due to crap that builds up in your system files. You install things and remove things and so forth. Some things just hang on in there forever and never getted clean up. A clean install does that.

widget:

Thanks very much for the info. I totally agree about the separate partitions for home folder. The 10.04 LTS installation on an external hard drive was my first Linux installation ever. I didn't know a thing about how to do separate partitions, etc. Now, I recently installed 12.04 LTS on a laptop and I did as you said, separate partitions for / and /home. My concern here on this upgrade is that I read, I guess from the Ubuntu help forums that upgrades should be done sequentially, meaning from 10.04 to 10.10, etc and what I will be doing is from 10.04 LTS to 12.04 LTS. You said:
Does this mean that there should not be any problem with this upgrade jump? This distro has served me well during the past three years, which have been mainly on learning Linux, and I don't want to loose important data accumulated. I already made a copy of my home folder on a separate drive. Is there any other folder that I should copy? Thanks again for the help.

If you were to upgrade from 10.04 to 11.10 this would be true.

You have to remember that the LTS release is Long Term Support. There are many people and even companies that want only a stable release.

LTS releases are not, therefore, like the regular releases. If you check the version number for your install of 10.04 you will find that it is 10.04.4. When that number changed if you downloaded 10.04 at that time the image would have included all package upgrades to that day. There are 4 step releases in the old 3 year support LTS releases (12.04 will have 5 year support and I don't know how many step releases).

That last step release includes some tools that make it possible to do a version upgrade from 10.04 to 12.04. While it is a bit tricky it works and 10.04 and 12.04 are capable of doing it.

I quit doing Ubuntu testing with 12.04 and did not do any upgrade testing from 10.04 to 12.04. I did however do testing on the upgrade from 8.04 to 10.04. 8.04 was easily as different from 10.04 as 10.04 is from 12.04 at least "under the hood" which is where it matters.

It should go fine. Make sure you have backups because any version upgrade can go wrong.

One thing you may not have considered in having a separate / and /home is that you can due a clean install of anything on that /. While I continued to do Ubuntu-testing through 12.04 I did a clean install of Debian Squeeze on my 10.04 /.

My wifes laptop will get a similar "upgrade" to Debian Wheezy when it goes stable.

You can also, making sure to use different user names, install 2 or more / partitions sharing one /home. This is a good way to do upgrades too. You can install the new version and have the old version still there to get your installs to match as much as you can.

One thing that ruins upgrades, particularly ones done with UM, is any repo that is not strictly Ubuntu. Medibuntu you can probably get away with. Any ppas you may be using should be removed.

This should be done with ppa-purge. Remove them and the packages they support. It will put the system in the shape it would be in if the ppa had not been there.

You can, when the version upgrade is done and working, put them back in.

widget:

Thanks again for the info. You said in your post something that got me worried:
I've got a few of those form launchpad.net, google.com, openprinting.org, linux.dropbox,medibuntu, etc. What are my choices to avoid problems? I've got a few applications from those sites that I need to keep and upgrade on a regular basis. Thanks for your patience.

When you run the version upgrade do not have them active in your /etc/apt/sources.list. Comment them out by adding a # at the start of their line.

In the case of ppas don't do that. Run;
I don't know if that is installed by default so check and make sure it is before running that command.

Think very carefully about what you are doing in a version upgrade.

One very good argument in favor of version upgrades is not having to reconfigure your OS. OK, this is a good argument for doing it.

You are using packages that are not part of the the distros repos. Those packages do require packages, usually from those repos as dependencies.

When you turn UM loose with a modified sources.list what it is doing is running a script. That script is using apt-get. So you tell UM to do a version upgrade. It then changes your sources.list to the target version. Then it runs "apt-get dist-upgrade" with some added extra. One is the clean up phase of things which is a secondary script relying mainly on "dpkg --configure -a" to correct problems encountered in upgrading some packages.

You are basically turning your system over to an automated tool. If you have an install that is cleanly built from the repos intended for that installed version it will work most of the time. Expecting it to upgrade a version custom built to your specifications is asking a lot of the devs that designed the tool.

I think it still probably works most of the time. How lucky are you feeling?

If you are installed on one partition (/) I would not do it with that kind of sources.list. I would back up everything you need data wise and probably all your ~/.hidden files (makes configuring the new system easier as that is where all your personal config files are) and do a clean install of the new version on 2 partitions.

Put add all the stuff you want to the new install and then just transplant the ~/.hidden files to it. Probably be a good idea to not use the Gnome specific ones as they are not going to be real relavent to the new system. You will have all your browser stuff there though and if you use Thunderbird I know all of it will be there. This is also where all your play lists and so forth for music players are.

And all of your config files for your added packages from outside repos.

I would not move the backed up data to the new install before getting the new install set up but that is not really a concern as long as you leave the backup files where they are in case of a wreck.

If you decide to upgrade the existing install make sure, very sure, that you have everything from the current setup that you could possibly want in the future backed up really safely.

widget:

What I gather from your last post is that the most trouble free way to do this upgrade is to backup my important files and then, do a clean install of version 12.04. Please, advice or correct the following steps, as necessary. I need this to be successful.

1. Backup Home folder (including hidden files)
2. Backup /etc folder (?) was suggested
3. Do a clean install on 2 partitions ( /, /home) of 12.04
4. Verify that installation is succesful (everything works)
5. Restore /Home folder to the new installation
6. Restore other folders (/etc)?

I know that the default mail app on 12.04 is Thunderbird, but the one I use on 10.04 is Evolution. What happens to the data and the local folders I've created in Evolution?
Thanks again for your assistance.

I am not sure how useful backing up the /etc directory is. There are some config files there that you may want though and so it wouldn't hurt.

There are more in /usr and that is where any themes or icons you have added will be. Not sure how useful backing them up will be though as you are going from Gnome 2 to Gnome 3 along with a switch from gtk2 to gtk3 so some theme engines may not work.

Not sure what the /LIST is referring to. If you want a list of install packages there are ways to do that but you have several thousand install probably. You know what applications you use and if you back up /usr/share/applications you will have them listed there.

I don't know what you do with wallpaper. Ubuntu uses /usr/share/backgrounds.

I never liked evolution but it will be in the repos if you want to use it. The config files should be in ~/.evolution or some other ~/.hidden directory and I would think your local files would be there. They have to be in user land so that your user and group owns them. If you were on a multi user install you wouldn't want the other user(s) to have access to those and they would feel the same about you.

I would think that setting it up would be a simple matter of just using your old files instead of the ones installed with it although I would put those files someplace safe before doing that in case there is some big change (I doubt it but it good to be careful).

You may want to consider a 3rd partition where you keep things like personal photos and your music librarly. Those files will degrade over time and being copied to new places. I have a data partition for them. You need to set that partition up manually in your /etc/fstab file along with creating a mount point in /media so that it mounts when you boot up. That way you can just point your music player there and simply navigate there to you images.

Has the advantage of not needing fooled with when you upgrade, reinstall or install another OS in a multi boot manner.

A shortcut is easy to set up in Nautilus (or was anyway) and in Thunar so I suppose this is true of most file browsers.