F15 to F17 preupgrade - problem with LVM and RAID?

Hi All

I am trying to upgrade two (64bit) machines (one laptop and one desktop) from Fedora 15 to Fedora 17 using preupgrade. The laptop worked fine but the desktop will not complete the upgrade.

I've searched on here and found two posts with what appears to be the same problem going from F11 to F12 and F14 to F15, but no solution.

I run preupgrade and it works up to the point at which the reboot happens. Then I get the following error messages.

Examining storage devices

Error processing LVM

There is inconsistant LVM data on Volume Group vg_dt001

You can reinitialise all related PV's (/dev/sdc1, dev/md127) which will erase the LVM metadata or ignore which will preserve the contents. This action may also be applied to all other PVs with inconsistant metadata.

I get the following options:

Ignore Ignore-all Reinitialise Reinitialise-all

I select Ignore and get the following:

Upgrade root not found The root for the previously installed system was not found

with the option to:

Exit installer

On clicking this the installer exits and the machine boots into Fedora 15.

I am thinking that this might be to do with the (software) raid that the system is running and possibly something missing from the F17 kernel the installer is using.

However, I'm unable to confirm this.

Can any one help?

How do I confirm what the issue is?
What do I do to fix it?

I'm loathe to complete the F17 upgrade by forcing a fix to the raid and then ending up with a system that boots neither F15 nor F17 :-)

Many thanks

Paul