Reinstalling Ubuntu 15.10: "Removing conflicting operating system files" has been running for almost 24 hours

Solution 1:

The main question is: do you have a separate /home partition? If so then just erase your / and leave /home untouched, just set mountpoint to it.

If not and there is some important files then I recommend you mount your partition and remove everything except /home, e.g.

fdisk -l

Examine the output and find appropriate device name

mount /dev/sdaXY /mnt  # use the device name from fdisk -l here
mkdir /mnt/2rm         # create working dir
mv /mnt/* /mnt/2rm     # move all dirs to work dir
mv /mnt/2rm/home /mnt  # return home back
rm -rfv /mnt/2rm       # now we can safely delete the rest

After the above manipulations you can easily install Ubuntu on the same partition. Ubiquity, the Ubuntu installer, will preserve your /home directory.