Here’s how to reinstall Ubuntu or another Linux distro without having to lost your app settings and data. It’s useful for some cases, for instance you won’t lost your Firefox bookmarks and login session, as well as browsing history and installed add-ons. Although you can regain them all easily by the new sync feature, it can help you to save bandwidth and time.
The key to accomplish this approach is at the partitioning section when you install from USB or DVD installer. If you have
/home directory in a distinct partition, then it will be easier to do. Otherwise, you may have to delete some system dirs first, instead of formatting
Once you have deleted directories other than
/home, select Manual when it comes to the partition section at the installation process.
/ (root) partition and use it as Ext4 or the previous format. But don’t check the Format this partition.
Another thing to note is that you have to take the same username as the previous installation. Since the installer will attempt to create
/home/username folder as your home dir. Then if the directory exists, it will not be overwritten though.