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🐧 Dual Boot Install Fix

Ubuntu Installer Does Not See Your Disk Turn Off RST the Safe Way

The installer opens, you click through — and there is no disk to install on, or a message about RST blocks the way. Your drive is healthy. It is hidden behind Intel's RST mode, which Linux cannot use. There is a safe way to switch it off, and a famous wrong way that leaves Windows unbootable. This page is the safe way.

✍️ Technical Anshu🐧 Ubuntu and Windows⏱️ 8 minute read
🎥 Watch the video — the dual boot installation this fix unblocks, shown live step by step

Many Intel laptops ship with their storage controller set to RST (Rapid Storage Technology), sometimes labelled RAID On in the BIOS. Windows has the driver for it; the Ubuntu installer does not, so to Ubuntu the drive simply does not exist. The fix is switching the controller to AHCI mode — but doing it in the wrong order trades one problem for a worse one, because Windows set up under RST cannot boot under AHCI until it is prepared. Prepare Windows first, flip the switch second. That order is this whole page.

Ubuntu installer — the message that stops the install
Turn off RST

This computer uses Intel RST (Rapid Storage Technology). You need to turn off RST before installing Ubuntu. Do not just flip the BIOS setting yet — prepare Windows first, or Windows will stop booting.

The installer's own warning, seen on Intel laptops in RST mode. The pages it points to describe the same safe switch this guide walks through.
1

Why the Disk Is Invisible

RST is Intel's storage layer — originally for RAID arrays, now often enabled by default even on single-drive laptops, sometimes tied to Optane memory setups. The Ubuntu installer has no driver for storage presented through RST, so the drive never appears in its list.

  1. The drive is not faulty, locked or too new — it is behind a mode Linux cannot see through
  2. The same machine installs Windows happily, which is why the problem confuses people
  3. AHCI is the standard mode every operating system understands, and the switch costs a single-drive laptop nothing in daily performance

Check your current mode in the BIOS setup — look for SATA Operation or Storage Configuration showing RAID On or RST, with AHCI as the alternative.

2

Do Not Flip the Switch Yet — the Blue Screen Waiting

Here is the famous trap. Windows was installed with the RST driver, so its boot is built around that driver. Flip the BIOS to AHCI with no preparation and Windows starts, cannot find its own drive, and stops with a blue screen.

  1. The error name is INACCESSIBLE_BOOT_DEVICE — it means exactly what it says
  2. Nothing is damaged; flipping the BIOS back to RST makes Windows boot again
  3. But you are then back at the start, with Ubuntu still unable to see the disk

The preparation in the next step makes Windows load the AHCI driver once, in Safe Mode, so the permanent switch becomes painless. Two minutes of preparation is the whole difference between the safe story and the blue screen story.

3

The Safe Switch — Safe Mode First, Then the BIOS

Do these steps in this exact order, in one sitting. Suspend BitLocker before you begin if your drive is encrypted — storage mode changes are exactly the kind of change it reacts to.

  1. In Windows, open an admin Command Prompt and run bcdedit /set {current} safeboot minimal
  2. Restart and enter the BIOS setup; change the storage mode from RST or RAID On to AHCI; save and exit
  3. Windows now boots into Safe Mode — and loads the standard AHCI driver as it does
  4. Open an admin Command Prompt again and undo the Safe Mode flag with bcdedit /deletevalue {current} safeboot
  5. Restart — Windows boots normally, now on AHCI, and the change is permanent

Sign in during Safe Mode with your password, not a PIN — Safe Mode asks for the account password. When Windows is confirmed booting normally, run the Ubuntu installer again and your disk will be listed.

4

BitLocker Will Probably Ask for Its Key Once

A storage mode change is a boot-path change, and BitLocker watches the boot path. Expect the recovery key prompt at the first normal Windows start after the switch, even with everything done right.

  1. Have the 48 digit key ready before you start — from your Microsoft account or manage-bde -protectors -get C:
  2. Suspending protection beforehand with manage-bde -protectors -disable C: usually skips the prompt entirely
  3. Turn protection back on once Windows and Ubuntu both boot happily

This is the same key discipline as the preflight checklist in this series — the switch is routine, but it is never the moment to discover you do not have the key.

5

If Your BIOS Has No AHCI Option at All

A minority of laptops hide the storage mode entirely or lock it to RST. Be honest about what that leaves you, because forum advice here gets reckless.

  1. Check for a BIOS update from your laptop maker — some models gained the option later
  2. Look under advanced or hidden BIOS menus; some brands reveal more settings with an advanced mode key
  3. If the option truly does not exist, this machine cannot dual boot the standard way — a virtual machine becomes the practical Ubuntu route

Do not chase registry hacks or modified BIOS files from random forums for this. Risking the firmware of your only computer to save a setting a menu should have had is a bad trade, and the honest answer is that a few RST-locked models are simply not dual boot candidates.

🔴 The order is the fix: Safe Mode flag first, BIOS switch second, flag removed third. Flipping the BIOS first is the single most common way people turn a ten minute job into an INACCESSIBLE_BOOT_DEVICE blue screen — and even then, flipping back undoes it.

🎥 Watch the Dual Boot Video

With the disk visible again, the video's complete dual boot installation runs exactly as shown — watch it live.

▶️ Watch Full Video
❓ Frequently Asked Questions

Will switching from RST to AHCI slow down my SSD

On a normal single drive laptop, no difference you can feel. RST's advantages are about RAID arrays and Optane caching setups; a plain NVMe or SATA SSD runs at its normal speed under the standard AHCI or NVMe drivers that Windows loads after the switch.

Windows shows INACCESSIBLE_BOOT_DEVICE after I changed the setting

That is the unprepared switch — Windows never got the chance to load the AHCI driver. Flip the BIOS back to RST and Windows will boot as before. Then follow this page in order: set the Safe Mode flag in Windows, switch to AHCI, boot once into Safe Mode, and remove the flag.

My laptop uses Intel Optane memory, does that change things

Yes — Optane caching is tied to RST, so disabling RST disables the Optane acceleration and the Optane device should be unlinked or disabled in its own Intel software first. If your machine relies on Optane, read the manufacturer's guidance for your exact model before switching, or stay with a virtual machine for Ubuntu.

This guide is based on the Technical Anshu video linked above • Stuck on a step? Ask in the video comments — you will get a reply 🙏