You may wish to reformat some of your legacy GNU/Linux partitions and to erase any data they contain. To do so, please select those partitions as well.

Please note that you don't have to reformat all pre-existing partitions. You must reformat the partitions containing the operating system (such as /, /usr and /var) but not the partitions containing data you wish to keep (typically, /home).

Please be careful when selecting partitions. After the formatting is completed, all data on the selected partitions is deleted and you won't be able to recover it.