If the error message No boot device available or No boot device found is displayed, it literally means " No boot device available " and it is a fairly serious problem, which prevents Windows from starting and loading the desktop. This error is displayed, with this written in English, on a black screen, without any indication, button or instruction on how to solve the problem and restore the PC.
The error of the No boot device indicates the impossibility for the computer to find and recognize the presence of the disk where Windows is installed. Therefore the PC freezes immediately and even a reboot does not lead to any result. This error may depend on the physical failure of the disk, but in most cases (at least for desktop PCs) it can be solved without having to bring the computer to assistance, as we will see in this post.
Sometimes it may be that the boot order of the computer is configured to search for the system on an external USB driver first, so just detach the external hard disk or the connected stick to correctly restart Windows.
You can easily solve this problem by going to the computer BIOS (see here how to access the BIOS), going to the Boot section and setting the disk where Windows 10 is installed as the primary boot.
You will then have to boot the PC from the USB stick and change the boot order from the computer BIOS. In this way, the PC will not try to boot from the disk it cannot find, but from the inserted USB stick.
When it begins to load the installation procedure of Windows 10, after accepting the conditions, click on the option Repair your computer . Under the Troubleshooting section, you can go to the Advanced Options and try using the Auto Repair tool .
In my experience this automatic repair has never solved anything, but it is definitely worth trying it immediately because it is a simple solution.
It is also recommended to disable the secure boot function and try to change the boot mode from UEFI to Legacy (these options may have different names depending on the version of the BIOS used, so if in doubt, look for the specific guide).
Otherwise you can try doing a BIOS reset.
By booting the PC from the USB stick with the Windows installation files as seen in Solution 4, Going to the Advanced Troubleshooting Options you can open a command prompt.
In the Command Prompt you can already check whether the Windows disk is recognized and run the following commands to restore the MBR:
If these commands don't work, try this:
READ ALSO: How to repair MBR on Windows to restore the computer startup
Then go to the command prompt as seen in Solution 6 (then from the USB stick with the Windows installation files) and proceed with the following commands:
sfc / scannow / offbootdir = c: / offwindir = c: windows
chkdsk c: / r
If it is still not resolved, try the DISM command (see also how to use DISM on PC)
DISM / Online / Cleanup-Image / RestoreHealth
If it still doesn't work, then try:
Dism / Image: C: offline / Cleanup-Image / RestoreHealth / Source: c: testmountwindows
Dism / Online / Cleanup-Image / RestoreHealth / Source: c: testmountwindows / LimitAccess
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Resolve the "Cannot find an operating system" error on Windows 10
The error of the No boot device indicates the impossibility for the computer to find and recognize the presence of the disk where Windows is installed. Therefore the PC freezes immediately and even a reboot does not lead to any result. This error may depend on the physical failure of the disk, but in most cases (at least for desktop PCs) it can be solved without having to bring the computer to assistance, as we will see in this post.
No boot device
The error message " No boot device available " can appear, depending on the computer in use and the cause of the problem, with different wordings, almost always in English.- No boot device found
- No boot device connected / selected / detected / available
- No boot device found press any key to reboot the machine (but pressing a key on the keyboard does not solve anything)
- No boot device has been detected (This type of message can appear if the hardware is defective or even if the disk is not connected correctly).
Solution 1: Check cables and USB ports
If the internal cables are not connected properly or are slow, the computer may not start and find no boot device. To solve this problem, you need to turn off the PC, disconnect it from the power outlet, open the computer case and check that the SATA cables that go from the disk to the motherboard are well fixed.Solution 2: disconnect each USB connection
Sometimes the computer may refuse to boot if one of the devices connected to it is defective. Then try to disconnect all the USB sockets, including the mouse and keyboard (I would also add the network cable) to see if it starts again.Sometimes it may be that the boot order of the computer is configured to search for the system on an external USB driver first, so just detach the external hard disk or the connected stick to correctly restart Windows.
Solution 3: Set the disk as the primary boot disk
As mentioned above, it may be that the boot order is wrong and that the computer, instead of looking for Windows on the disk in which it is installed, tries to load the files on a USB stick or on another internal disk.You can easily solve this problem by going to the computer BIOS (see here how to access the BIOS), going to the Boot section and setting the disk where Windows 10 is installed as the primary boot.
Solution 4: Use automatic repair
While nothing can be done with the PC, it is always possible to start it using a USB stick with the Windows 10 installation files inside. As for other types of errors when the PC does not start, you need to download the ISO of Windows 10 and copy it on a USB stick (using Microsoft's Media Creation Tool it's easy to do both at once).You will then have to boot the PC from the USB stick and change the boot order from the computer BIOS. In this way, the PC will not try to boot from the disk it cannot find, but from the inserted USB stick.
When it begins to load the installation procedure of Windows 10, after accepting the conditions, click on the option Repair your computer . Under the Troubleshooting section, you can go to the Advanced Options and try using the Auto Repair tool .
In my experience this automatic repair has never solved anything, but it is definitely worth trying it immediately because it is a simple solution.
Solution 5: Change the BIOS setting
The No Boot device message can occur after a BIOS update or after changing some hardware settings related to the disk configuration (for example, after trying to activate AHCI for quick PC startup or after trying to switch from BIOS to UEFI and convert the disk to GPT). To solve the problem, it can be enough to find, in the BIOS, the option that activates UEFI (if present).It is also recommended to disable the secure boot function and try to change the boot mode from UEFI to Legacy (these options may have different names depending on the version of the BIOS used, so if in doubt, look for the specific guide).
Otherwise you can try doing a BIOS reset.
Solution 6: Restore the boot sector
The boot sector of the PC, called the Master Boot Record, is that part of the disk where the instructions to start the computer are stored. If the error had been of the "Non system found" type then this was the first solution to try, while in this case, if it is "No boot device found", it means that the disk is not detected, therefore it is not even boot sector loaded. Still worth a try.By booting the PC from the USB stick with the Windows installation files as seen in Solution 4, Going to the Advanced Troubleshooting Options you can open a command prompt.
In the Command Prompt you can already check whether the Windows disk is recognized and run the following commands to restore the MBR:
- bootrec.exe / FixMbr
- bootrec.exe / FixBoot
- bootrec.exe / RebuildBcd
If these commands don't work, try this:
- bcdedit / export C: BCD_Backup
- c:
- boot cd
- attrib bcd -s -h -r
- ren c: bootbcd bcd.old
- bootrec / RebuildBcd
READ ALSO: How to repair MBR on Windows to restore the computer startup
Solution 7: Use the SFC scan
If the disk is not broken and there are no problems with the BIOS settings or even with the MBR, the computer may be experiencing a problem in the current installation of Windows 10 that needs to be repaired. The choice, then, is to reinstall the system or to use the SFC Scan tool which restores the files.Then go to the command prompt as seen in Solution 6 (then from the USB stick with the Windows installation files) and proceed with the following commands:
sfc / scannow / offbootdir = c: / offwindir = c: windows
chkdsk c: / r
If it is still not resolved, try the DISM command (see also how to use DISM on PC)
DISM / Online / Cleanup-Image / RestoreHealth
If it still doesn't work, then try:
Dism / Image: C: offline / Cleanup-Image / RestoreHealth / Source: c: testmountwindows
Dism / Online / Cleanup-Image / RestoreHealth / Source: c: testmountwindows / LimitAccess
Other solutions
We have seen other guides to deal with problems of this type, when the PC does not start or Windows does not load properly and it is worth reading them for a broader overview and alternative solutions (even if there is nothing to do).How to turn on the PC if Windows does not start
What to do if the computer hard drive is broken or damaged
What to do if the screen remains black and nothing is seen
Resolve the "Cannot find an operating system" error on Windows 10
