Troubleshoot installation failures

• You might have an issue with your USB drive—From time to time, Sandisk or other USB drives might not work as installers. Try creating a new USB installer with a USB drive from a different manufacturer. Find out more in Known issues.
• USB Boot is turned off—Check the BIOS or UEFI settings on your device and make sure that USB boot is turned on.
  Note: The option name differs, depending on the OEM. Look out for USB boot, Boot from external media, or similar settings.

• Unsupported device—Check to see if the exact model is included in our Certified models list. While ChromeOS Flex might work on non-certified devices, we do not guarantee performance, functionality, or stability.
• Corrupted USB—See I can’t boot my device from the USB installer above. If you’re not sure whether the issue is caused by the USB installer itself or the device’s USB port, test the USB installer on other devices to see if it works.
• USB port or dongle issue—Sometimes, devices might struggle to boot from a particular USB port or dongle that the USB drive is attached with. Try using different USB ports and dongles and see if your issue resolves.

The installation script can’t find a valid install destination.

Bear in mind:

• ChromeOS Flex only considers drives that are larger than approximately 16 GB to be valid install destinations.
• ChromeOS Flex rules out the USB installer it is running on.
• ChromeOS Flex tries to rule out removable media so that install destinations are internal drives only.
• Occasionally in the past, ChromeOS Flex has not been able to recognize newer or unusual types of internal storage. This seems to no longer be an issue.

Troubleshoot

Step 1: Check to make sure the device meets requirements

• Make sure the device has working internal storage, such as a HDD, SSD, or eMMC.
• Check that the device’s internal storage is greater than 16 GB.
• Check the connection to the internal storage, if it’s physically accessible.
• Make sure you're using a certified model and check install notes. See the Certified models list

Step 2: Re-install ChromeOS Flex on the device

1. Re-create the USB installer. For instructions, see Create the USB installer.
   Tip: Consider using a new USB drive from a different manufacturer.
2. Open the BIOS settings menu. If you’re unsure which key to use, see Boot keys below.
3. Reset the BIOS to default settings.
4. In the BIOS settings, check your boot order to make sure the correct drive has been selected.
5. In the BIOS settings, turn off the Trusted Platform Module (TPM). For instructions, see Deactivate TPM.
6. Save the settings and exit the BIOS settings menu.
7. Re-install ChromeOS Flex on the device. For instructions, see Boot device using the USB installer and Start using ChromeOS Flex.

Step 3: Change settings from RAID to AHCI

ChromeOS Flex cannot install if internal storage—such as HDD, SSD, and so on—is set to RAID mode. Before you install ChromeOS Flex on devices, switch BIOS or UEFI settings from RAID to AHCI.

1. Open the BIOS settings menu. If you’re unsure which key to use, see Boot keys below.
2. Find the menu for RAID and AHCI settings, typically under Storage.
3. Make sure that RAID is set to Disabled or switch from RAID to AHCI.
4. Save the settings and exit the BIOS settings menu.
5. Re-install ChromeOS Flex on the device. For instructions, see Boot device using the USB installer and Start using ChromeOS Flex.

When booting from the ChromeOS Flex installer, you might see an error on your device letting you know that no OS was found.

Before you begin: Recreate the USB installer using Chromebook Recovery Utility. Most of the time the No operating system found error occurs because the USB drive is corrupted or the image did not properly load. For instructions on how to create the USB installer, see the ChromeOS Flex installation guide.

Troubleshoot

If you see the 1962: No operating system found error while trying to boot from the USB installer:

1. After you insert the ChromeOS Flex USB installer, on the Startup device menu, be sure to choose UEFI: USB Name.
2. Open the BIOS settings menu. If you’re unsure which key to use, see Boot keys below.
3. Find the CSM and Boot Mode settings. Make sure that CSM is set to Enabled and Boot Mode is set to UEFI Only.
4. Save the settings and exit the BIOS settings menu.
5. Continue with the ChromeOS Flex installation.
   The device should shut down and reboot in ChromeOS Flex.

For ASUS models, if you see the 1962: No operating system found error after you finish installing ChromeOS Flex:

1. Open the BIOS settings menu. If you’re unsure which key to use, see Boot keys below.
2. Reset the BIOS to default settings.
3. While the device is booting, press ESC and select UEFI: USB Name.
4. When ChromeOS installation finishes:
   1. Remove the USB drive.
   2. Open the BIOS settings menu and create a new boot option.
   3. Select the path for the boot option from the device’s hard drive, /efi/boot/bootx64.efi.
   4. Save the changes.
5. Reboot the device to use ChromeOS Flex.

If the issue persists or the boot option fails to save changes, using the BIOS settings menu, turn on Pre-boot Execution Environment (PXE) to set the network as a boot device. Repeat the steps above. After you create the boot option, you can turn off PXE again.

We include a number of Mac devices in our Certified models list. While devices usually work as expected, sometimes ChromeOS Flex successfully installs but then a significant or indefinite delay occurs. Subsequently, when you try to boot ChromeOS Flex, you might see a black screen on the device.

Troubleshoot

Option 1: Manually set a default boot option

1. Remove the ChromeOS Flex USB installer from the device.
2. Boot the device and view the list of available boot options. If you’re unsure which key to use, see Boot keys below.
   1. Press the power button.
   2. Immediately begin repeatedly pressing your device's boot key.
3. If ChromeOS Flex is correctly installed, you’ll see one option that’s called EFI Boot or ChromeOS Flex.
4. Set the default boot option. You can use your mouse or the arrow keys on your keyboard:
   • Mouse—Press Ctrl on your keyboard and left-click EFI Boot or ChromeOS Flex.
   • Keyboard—Use the arrow on the keyboard to select EFI Boot or ChromeOS Flex. Press Ctrl and Enter.

If you’re still having issues, follow the steps below to clear logic board RAM.

Option 2: Clear logic board RAM

Mac devices have memory on their logic board, known as parameter RAM (PRAM) or non-volatile RAM (NVRAM). Among other uses, logic board RAM remembers the default boot device. After ChromeOS Flex is installed, the logic board might continue to look for the previous OS-X or macOS install that it expects.

Note: We recommend that you do not reset NVRAM on very old Apple models, including iMac 5,2, Macbook 2,1, Macbook 3,1, and Macbook 4,1. From time to time, they lose functionality when NVRAM is reset.

1. Completely shut down the Mac device.
2. On your keyboard, press cmd+opt+p+r and turn on the device.
   Note: For Windows keyboard, press win+alt+p+r.
3. Continue pressing the key combination until you hear 2 start-up chimes. It might take a few minutes.
   Note: Make sure that you hear and count 2 chimes. If you’re unsure, it’s ok to let the device chime more than 2 times.

The logic board RAM is now cleared. You might need to reset brightness and volume on the device. Boot time might significantly improve. In some cases, you might even be able to fix a total failure to boot.