Yesterday I tried installing Fedora 10 DVD 64bit to dual-boot with Windows and it broke almost all my partitions although I had chosen partitioning correctly in the installer. This is my configuration and the steps I followed in detail:

My partition and HDD configuration is two hard disks partitioned like this: HDD1 (main hard disk): 1st partition - NTFS with Windows XP installed (C:). 2nd partition - Linux ext3 on which I had Linux Opensuse 11 installed - 3rd partition: Linux swap. 4th partition - Another NTFS partition on which I store files (No OS installed, extended). HDD2 (secondary hard disk): A single NTFS partition on which I store files again, this HDD should not be touched by the installer in any way except mounting.

So before the install I had Windows XP and OpenSuse 11 dual-boot installed over the configuration above and working correctly. As written above, both Windows and Linux are installed on the same main HDD but in different partitions.

Yesterday I tried replacing Opensuse with Fedora 10 which I want to use now, and tried installing it by formatting the partitions Opensuse was on and putting Fedora 10 there instead, of course without touching any NTFS partition and being able to still dual-boot Windows XP and Fedora.

When the Fedora 10 setup reached the partitioning part, I chosen the option "Use only Linux partitions" (or something like that) from the drop-down menu, then checked the checkbox "review my partition setup". When I clicked Next I entered the list showing me the partitions that would be used. They were exactly as I wanted them to so I clicked Next and started installing.

A note to add here: By default the setup wanted to install the bootloader on HDD2, my alternative HDD which I use for storing files that should not be touched by the installer in any way. However from the drop-down list showing both of my hard disks I selected the correct one manually (HDD1 where Linux and Windows were).

After Fedora finished installing all packets and asked me to restart, when my computer attempted to boot from my hard disk again it said "Grub loading..." like its normal but then "Error: 7" and stopped there, which means the bootloader did not install correctly (I got no error messages during the Fedora install btw). When I got to see my partitions with the Windows XP install disk, this is how my partitioning changed after Fedora attempted to be installed:

HDD1: C: on which I previously had Windows had become D:, and D: became E:. As for the Linux partitions which had to be (re)used, the little one which I think should have been swap was ext3 instead, while the larger one which Linux should have been on had some sort of format called "Windows recovery partition" or something like that (I think a corrupted partition format). There was also some "unknown disk" in the partitions list there...

HDD2: Although the NTFS partition I had there was still readable from windows which helped me save my data, the partition table of that hard disk was corrupted which could be seen with partition management software. I had to transfer my data, reformat and repartition the entire HDD and put it back in order to fix it.

Sadly the only steps to reproduce is trying to install with the same configuration on a partition and HDD layout similar to mine. This is all detail I remember but if Fedora 10 can do that to the partitions while its setup is set so everything goes correctly it might be a very major issue.