Reinstalling Ubuntu without formatting /home

Solution 1:

Your home folder contains your user data, which obviously you want to preserve. Your home folder however also contains user configuration files of software. These, you do not want to preserve, and certainly not versions from Ubuntu 14.04 for use in Ubuntu 18.04. There is no guarantee that newer versions of software use the same format of configuration files. Therefore, leaving your old configuration files in place might cause you to waste (a little) disk space at best, but might at worst cause less or more severe issues with the functioning of the software.

For this reason, on a new install with a separate home partition, I always move my old home folder out by renaming it eg from vanadium to vanadium_old. Then, I do a fresh install where the home folder is not formatted. As such, a 'factory-fresh' new home folder vanadium is created by the installer. I then move the contents of my folders Documents, Pictures, etc. in the old home folder to the new home folder. The procedure is:

1. Boot the installation CD or USB into a live session
2. Mount your home partition
3. On your home partition, rename your home folder to <login>_old, where <login> is the current name of your home folder, typically the same as your login.
4. Unmount your home partition
5. Start the installer program (if you forgot unmounting your home partition, the installer will offer you to unmount it)
6. In the Installer, choose "Something else". You come into the manual partitioning screen. Assign your existing root partition to / and assign your home partition to /home. Important: make sure to remove the checkmark "Format partition" for your home partition in order not to have the data erased. That checkmark will be set by default.
7. Continue installation. Make sure to provide the same user name <login for the account that will be created.

After installation, you can move the data from \home\<login>_old to \home\<logon>. I usually leave the old folder for a while, but in principle, that can be deleted when the data are moved.

You must of course know a bit about partitions. A minimum of technical knowledge is required if you want to deviate from standard installation procedures. If you really do not have an idea which one to select during installation, and you do not have the time to read you in a little bit, then I recommend a different procedure:

1. Make sure the backup of your data is up to date
2. Perform a standard fresh installation where the existing Ubuntu 14.04 is being wiped. This also wipes your configuration data and user data.
3. Restore your data from the backup