I've converted my dirrerencing Windows XP disk to a dynamically expanding disk by merging it with the parent. This new merged disk boots just fine, but ofcourse still has the same old size. So I added it as a secondary disk on a Windows Server 2003 machine, and followed these points to expand the disk:

-Gave it a drive letter in Administrative Tools-> Computer Management-> Disk Management
-Ran DISKPART:

DISKPART>list disk
DISKPART>select disk 1
DISKPART>list part
DISKPART>select part 1
DISKPART>extend
DISKPART>exit

-Removed the drive letter in Administrative Tools-> Computer Management-> Disk Management
-Exited Widows Server 2003
-Changed the primary vhd of my Windows XP machine to the new extended disk

When I try to boot the Windows XP machine it now fails with a "A disk read error occured. Press Ctr+Alt+Del to restart"

Has the resizing operation somehow corrupted the disk or have I made some other error in the prosess?

I had the same problem -"a disk read error occured" and the VW wouldn't boot.  I tried it a couple of times, tried dismounting and mounting, all sorts of things, but I couldn't get past the problem.  I just went back to my backup.  *shrug*.   If someone finds a resolution to this problem, I'm all ears, but for now I've got to say the product doesn't do what it says on the tin.

You might want to take a look at the following link.

 http://searchwincomputing.techtarget.com/originalContent/0,289142,sid68_gci1126671,00.html

 This might help with increasing the size of your VHD.  I see that you tried to increase the partition size but I think you should have done the volume instead.

This article doesn't fix the problem. I get the "disk read error" before and after using diskpart.

Im getting this too.. had a 3Gb W2k3 vhd tried to resize it to 20gb .. no go.. tried again to 8gb no go. This is resizing the image file itself using the utility not the partition.

I have solved the issue by modifying the Virtual Machine BIOS parameters:

1. While booting, press DEL to enter setup.
2. Go to Advanced menu
3. Select IDE Configuration
4. Select Primary IDE Channel (0) (or the relevant drive)
5. Disable LBA/Large Mode
6. Save settings and exit

I haven't noticed any performance degradation due to this setting.

Please let me know if this solves your problems as well.

That fixed the disk read error for me.

 

Thanks

murat- you are a star - I don't think I would ever have guessed that!

Thanks a lot.

that sounds easy to do, but what about people running Virtual Server 2005?  I can't get into the BIOS.

WinXP Pro, SP1 in the VMC, running on XP Pro SP3.

Doesn't work for me, currently trying various combinations.

 At first I thought it was because I may not have shut down my VMC prior to running the resizer, so ran through it all again having first shut down the VMC... no luck.

 Tried Murat's suggestion of switching off LBA/Large Mode for the new disk... no luck. (interestingly, my "old" VHD drive only works if I have LBA/Large Mode switched on to "auto").

Would like to see if anyone else had issues.

Ya! Doesn't work for me too... The pointer goes haywire while booting. It never enters the boot screen of the OS hosted, but the pointer jumps around randomly after I tried murat's method.