I installed a Windows Server 2016 in a physical server with RAID 10 (LSI card), whose configuration is shown below:

enter image description here

Even though the RAID configuration shows one 3.725 TB drive, this shows up as 2 disks in windows.

I installed the operating system and it shown 2 disks during installation, and it now still displays 2. THe weirdest thing is that I can't even initialize the disk:

enter image description here

What am I missing here?

This is what I see in the windows installer:

enter image description here

The two items at the bottom are the 2 parts of the disk (I believe this is due to MBR limiting the size to 2TB) and then when I choose the first unallocated space to create a 300GB partition for windows, the other one above is created automatically.

I do this, and when I am inside windows I can't do nothing with the second unallocated space.

I have now tried booting the installer, hitting Shift+F10, and using diskpart to convert to GPT.

When I do that, I see the ~4TB as a single unallocated space, but once I create a partition, it shows me the 2 unallocated spaces again and I can't install, I receive an error from windows.

If I leave the 4TB as a single unallocated space and hit next, it is installing (at this moment).

Not sure if it will boot windows afterwards, or if I will be able to create partitions after that...

2 Answers 2


Your Windows installation seems to use the legacy MBR for partitioning, which means you can allocate at most 2 TB (which is in-line with your C + D total allocated space).

You need to reinstall Windows with GPT partitions, or do an in-place conversion to GPT. After that, you can expand your D partition to cover all available disk space.

As a side note, I strongly suggest creating two virtual drives: a ~80 GB one for Windows (with classical MBR) and a second one, with GPT formatting, covering all the remaining space. This second drive can be configured and brought online directly from Windows disk management utility (which give more control options compared to the install screen).

  • Can I choose MBR and GPT types from within the LSI Megaraid virtual drive configuration? Is that what you are suggesting? Dec 26, 2019 at 11:50
  • MBR vs GPT generally is a OS choice; however, if you can set it in the virtual drive config, let's try it. Be aware that with these experiments you can (and probably will) clear all data from the drives, so be careful if the server contains "live" data. As always, be sure to have a working, up-to-date backup.
    – shodanshok
    Dec 26, 2019 at 16:39
  • No problem with data, this is a server that is being configured for the first time - well multiple times given the fact that setup isn't behaving as it should :) Dec 26, 2019 at 17:33
  • Just to confirm that creating 2 virtual drives fixed the issue. The first one uses MBR and I installed windows in it, and the second one was initialized after windows installation and windows automatically suggested setting it up as GPT. Thank you. Dec 28, 2019 at 12:11

That’s not what the Windows screenshot says. Windows sees a single disk (plus your CD), which has been partitioned for booting windows, plus a data partition, with 1.7 TB of space not assigned to partitions yet. You “can’t” initialize the empty space since the disk is already initialized and partitioned, but you can surely extend your D partition or create a new one using the empty space.

  • Your answer does not describe the situation correctly. The windows setup shows the single disk as 2 unpartitioned storages, and I can't even select the second for installation. I need to create a partition in the first storage space (2TB) and I can't initialize, create or extend the D partition. Will add a few extra screenshots and info in the question. Dec 26, 2019 at 11:00

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