Virtual Hard Drive not showing up in virtual machine guest OS

Jon Scriven
Jon Scriven used Ask the Experts™
I am trying to add an extra virtual disk to a VM running Windows Server 2008 R2.

The first time I tried to do this, it Blue Screened.

Detail here:-

This problem was resolved, but I removed the extra drive whilst troubleshooting the problem.

Second time around things have gone a bit more smoothly (i.e. the server is still alive), however it can't see the disk in DISKPART or DISK MANAGEMENT.

I am at a bit of a loss as to what is happening as I have added disks to VM's plenty of times in the past and it has usually been quite easy.

I have removed the disk (including files) and added again.  Done several reboots.  Done rescans from all of the disk tools, scanned for hardware changes in Device Manager and have tried removing and readding the disks whilst the OS is Shut down and when it is up and running, but it just cannot see the disk (SCSI 0:4)

Disk showing in VMware:-

VM Properties
LS on ESX server
Not visible in Diskpart or Disk Management:-

Disk Management
This is a live production system, so if you are expecting me to do anything such as rebooting, then it might take a while to arrange downtime......

Any ideas?
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In the last screen shot, if you scroll down to the item under the CD-ROM, what is it? The scroll bar shows there is another item in the list that is not displayed.

It is possible it added the disk, but is not initialized. Scroll down to the bottom of that list and you may find an unallocated or un-initialized disk.
Although very unlikely It may be your windows system has already seen the disk signature but it's been removed. In this case it will not add it to disk manager again.
There is a method to resolve this but it's quite fiddly.
Run these commands in a dos box
set devmgr_show_nonpresent_devices=1
cd  %SystemRoot%\System32
start devmgmt.msc

this will start Device Manager, select view->show hidden.
now have a look in Storage volume (in device manager)
any greyed rather than solid devices can be deleted.In fact a rescan of your hardware would put anything back that you require if you deleted saomething that's required. OH keep way from "Non plug and Play", keyboard and mouse..

I must ask why you are using the dreaded dynamic disk.?
Jon ScrivenSenior IT Infrastructure Officer


Oh, if only I had thought to scroll down to the bottom of the page....

Oh, yes, I did actually.  Thanks for the slightly patronising suggestion, but I only didn't include the bottom part of the screen to reduce the file size.  Besides, if this was the case then it still would have shown up in DISKPART.

Disk Management part 2
markzz - just trying your suggestions now.
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Jon ScrivenSenior IT Infrastructure Officer


Hi Markzz,

There was nothing hidden, but in looking through all the Device Manager drop downs to find something different, I did locate the hardware in Other Devices instead of being in Disk Drives.  I will look at why this is now.  Please let me know if you have any ideas.....

Device Manager
I don't know why they are using Dynamic Disks, I did not set this server up, but I imagine it is so that the disk can be easily resized at a later date.

Is there a reason why they shouldn't be using Dynamic disks?
Jon ScrivenSenior IT Infrastructure Officer


OK - I have found this:-

which in turn has led me to this:-

This looks a lot like the original problem I had (see the other EE link in my original post) and I am just working through the steps now.
Senior IT Infrastructure Officer
So it is all working now.

The link I found earlier resolved it (with help from markzz who helped me to spot the drive lurking in Device Manager!)

I followed this from step 5:-

When I went back into Disk Management, it spotted the drive and is now showing in the correct place in Device Manager too.

Initialise Disk
Disk Management (version 3)
Thanks for your help!
Jon ScrivenSenior IT Infrastructure Officer


I found the solution in the end, but Markzz's suggestion pointed me in the right direction.

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