Comment 4 for bug 982473

> Could you please describe the setup of your system before you installed
> Precise Beta 2 and the steps you follow to install Beta 2 and get this
> error ?
>

My setup is Lenovo R61 notebook with single SATA HDD. I have old
installation of the Pangolin beta 1 system.

I tried to over-install beta 2 on my screwed btrfs-partition (upgrade
failed previously and broke libc6*). But independently from the notice the
old configuration of the system seem to be not deleted from the partition
before installation. It was chosen custom partitioning, then to existing
partitions I added tags to /boot (/dev/sda3), / (dev/sda2), I do nothing to
swap (/dev/sda1).

> I also noticed from the logs that a custom source.list and a ppa are
> enable:
> http://apt.spideroak.com
> http://ppa.launchpad.net precise
>

That was on original system before it fails.

> And this errors
> Apr 15 13:30:19 ubuntu ubiquity: ERROR: '/target//@' exists
> Apr 15 13:30:49 ubuntu ubiquity: ERROR: '/target/home/@home' exists
>

And yes - these are my volumes on btrfs partition created during
installation of beta 1. I later add /boot ext2 parition (resizing) to avoid
problems with grub2.

For me this is strange that the installer cannot fix the existing broken
installation or just cleanly overinstall without touching /home.

* - I finally succeed with removing it from that partition but failed on
restoring it.