Complete Guide to Installing Dual Boot Windows 11 and Ubuntu on Dell Laptops

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After years of using Windows 11, I wanted to explore Ubuntu for coding, automation, and Linux-based projects.

But setting up a dual-boot system on a Dell laptop wasn’t as straightforward as I expected — especially with Dell’s RAID configuration and Intel RST storage system.

Here’s my complete journey — the steps I followed, the BIOS issues I faced, and how I finally got Windows and Ubuntu to live together in peace.

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Step 1: Creating a Restore Point (Absolutely Important!)

Before changing anything, I created a System Restore Point on Windows 11.
Think of it like a “time machine” — it saves your system’s current state, so you can roll back if anything goes wrong.

💡 Why it’s important:

• BIOS or partition changes can sometimes corrupt Windows boot loaders.

• Dual boot setups may accidentally overwrite EFI or MBR records.

• A restore point ensures your system can be recovered without reinstalling everything.

🪄 How to create it:

1. Search “Create a Restore Point” in Windows search.

2. Choose your C: drive and click Configure → Turn on system protection.

3. Set maximum usage (around 5–10%).

4. Click Create, give it a name (e.g., “Before Ubuntu Install”), and save.

💾 Pro tip: Combine this with a full backup of your important files.

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Step 2: Creating a Separate Partition for Ubuntu

Ubuntu needs its own space to live.
Instead of creating a new drive, I simply shrunk the main volume to make space.

🪜 Here’s how:

1. Press Win + X → Disk Management.

2. Right-click your C: drive → Shrink Volume.

3. Enter the space you want for Ubuntu (at least 50GB recommended).

4. You’ll now see Unallocated Space — don’t format or assign a letter.

This un-allocated space will later be used during Ubuntu installation.

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Step 3: Creating a Bootable USB Drive for Ubuntu

I downloaded the latest Ubuntu ISO from ubuntu.com/download.
Then I used Rufus to create a bootable USB drive.

⚙️ Rufus settings I used:

Device: USB drive Boot selection: Ubuntu ISO Partition scheme: GPT Target system: UEFI (non-CSM)

Click Start, wait for it to finish, and safely eject the USB.

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Step 4: Changing Dell BIOS Settings (The Tricky Part)

After inserting the USB drive, I restarted my Dell laptop and pressed F2 to enter BIOS.
When I selected the USB drive to boot from, I immediately got a storage-related error — Ubuntu couldn’t detect the disk.

That’s when I learned that Dell systems come configured with RAID mode (Intel Rapid Storage Technology), which Ubuntu doesn’t support by default.

Here’s how I fixed it:

1. Restart and press F12 → BIOS Setup.

2. Go to Storage Configuration.

3. Change the option from RAID → AHCI.

4. Save and Exit.

💡 Do NOT change the drive priority or disable boot devices unless necessary.

Now, Ubuntu recognized the drive perfectly.

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Step 5: Installing Ubuntu (Manual Mode)

When Ubuntu loaded the GRUB menu, I selected “Try Ubuntu” to make sure everything worked.

Then I started the installation manually instead of choosing the recommended “Install alongside Windows” option.

What I did:

1. Selected Manual Partitioning.

2. Chose the Free Space I created earlier.

3. Created a new partition:

   • Mount point: /

   • File system: ext4

4. Selected the option to install updates and third-party drivers (Wi-Fi and graphics).

Once done, Ubuntu installed smoothly.
I unplugged the USB and restarted.

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Step 6: The Boot Problem — Windows Not Loading

After installation, GRUB appeared — showing both Ubuntu and Windows.
But when I selected Windows, I got an error message.

Here’s how I solved it:

1. Restart → Press F12 → Enter BIOS again.

2. Go to Storage Configuration → Switch back to RAID mode.

3. Save changes and exit → Windows booted perfectly!

But now Ubuntu stopped loading — so here’s the crucial next step.

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Step 7: Enabling AHCI Support in Windows (The Crucial Fix)

To make both OSes work under AHCI mode, I had to enable AHCI drivers on Windows safely.

Here’s how:

1. Open Run (Win + R) → type msconfig → press Enter.

2. Go to Boot tab → Safe Boot → Minimal → Apply and restart.

3. During restart → Press F12 → BIOS → Switch to AHCI → Save & Exit.

4. Windows booted in Safe Mode under AHCI and installed the drivers.

5. Open msconfig again → disable Safe Boot → restart normally.

Now both Windows and Ubuntu worked perfectly under AHCI mode!

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Step 8: Pro Tips Before Dual Booting

Here’s what I learned from this journey:

• Disable Secure Boot in BIOS before installing Ubuntu.

• Turn off BitLocker encryption — it can block partition changes.

• Always backup files and create a Restore Point.

• Use manual partitioning for better control.

• Keep Rufus and BIOS firmware updated.

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Final Thoughts

Dual booting is like teaching two powerful operating systems to share one home.
On Dell laptops, RAID vs AHCI is the main challenge — once you understand it, the rest becomes a smooth ride.

Now I can enjoy both worlds — Windows for productivity and Ubuntu for development — without conflicts.
watch this video to below

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Have you ever faced issues installing Ubuntu or dual booting on a Dell laptop?
Share your experience in the comments — I’d love to hear how you fixed it!

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✍️ Written by Aravind Kumar Yedida — a tech enthusiast sharing real-world fixes.