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December 5th, 2025 04:45
Unable to Format Rack Server – PowerEdge R740
We have a rack server (Dell PowerEdge R740) that needs to be formatted because the system is corrupted and we need to rebuild the OS. However, we are unable to format it. We have already tried booting with a bootable USB drive as well as a CD, but the server is not proceeding with the format in either case.
Requesting your support to help us resolve this issue and guide us through the proper steps to rebuild the server.
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Dell-Martin S
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December 5th, 2025 12:40
Hi,
Here is a step-by-step guide to narrow down the problem and successfully rebuild the server.
Step 1: Check Boot Mode (UEFI vs. BIOS)
The R740 is set to UEFI by default. If your USB stick or CD was created for the old "Legacy BIOS" mode, the server will ignore the media or will not be able to boot from it.
Start the server and press F2 (System Setup) once the Dell logo appears.
Go to System BIOS > Boot Settings.
Check the Boot Mode. It should be set to UEFI (recommended for modern OS).
Note: If you absolutely need legacy, switch it here, but most modern installation media (Windows Server 2016/2019/2022, ESXi 7/8) requires UEFI.
Make sure Secure Boot is set to Disabled for the time being if you want to boot from unsigned media or older Linux distros.
Step 2: Using the Lifecycle Controller (The Cleanest Method)
Dell servers have a built-in tool called Lifecycle Controller. This is the safest way to install the OS, as the server automatically provides the necessary drivers for the storage controller (RAID).
Restart the server and press F10 (Lifecycle Controller) when the Dell logo appears.
From the menu on the left, select OS Deployment.
Click Deploy OS.
Step 1: If you have not yet configured the RAID or want to delete it, select Configure RAID First. If the RAID already exists and is okay, select Go Directly to OS Deployment.
Tip: If you want to "format", it is often best to reconfigure the RAID here (erase and recreate Virtual Disk) so that the disks are really "empty".
Step 2: Select your operating system (e.g. Windows Server 2019) and boot mode (UEFI).
Step 3: The server will now prepare drivers. If he asks you, insert your CD or plug in the USB stick now.
The server reboots and boots directly into the installation. Since the drivers are now loaded, the hard drive will be visible in the Windows/Linux setup.
Step 3: The "Driver Problem" (If you boot directly from the USB stick)
If you don't use method 2 (F10) and boot directly from the USB stick (via F11 Boot Manager), the following often happens: The installer starts, but it doesn't show any hard drives.
This is because standard Windows images do not have drivers for the PERC (PowerEdge RAID Controller).
Solution: You need to download the PERC driver (e.g. for PERC H730P or H740P) from the Dell website, copy it to the USB stick and click "Load Driver" during installation.
Alternatively, use step 2 (Lifecycle Controller), as it solves the problem automatically.
Step 4: Format the Disks (Erase Virtual Disk)
If you say "it doesn't format", it could also be that the disks still have an old partition table that is locked.
Start the server and press F2 or Ctrl+R (on older controllers) to get to the Device Settings menu.
Select your RAID controller (e.g. RAID controller in slot 1: Dell PERC H730P).
Go to Virtual Disk Management.
Here you can see your "Virtual Disk". From the Operation menu, choose -> Initialize (or Fast Initialize).
This deletes all data at the logical level.
If you want to be on the safe side, you can also delete the virtual disk and create a new one. This is the most effective "formatting" at the hardware level.