When booting your Windows PC, you may encounter the black screen issue with the “An operating system wasn’t found. Try disconnecting any drives that don’t contain an operating system. Press Ctrl+Alt+Del to restart” error message. This post from MiniTool tells you how to fix the issue.
On This Page :
When you try to boot your system after updating the system, installing a new SSD, or updating BIOS, you may receive the “An operating system wasn’t found. Try disconnecting any drives that don’t contain an operating system. Press Ctrl+Alt+Del to restart” error message with the black screen.
The most common reasons for the “an operating system wasn’t found” error are as follows:
- Corrupted system partition
- Missing or damaged MBR (Master Boot Record)
- No active partition or wrong disk partition marked as active
- Corrupt boot configuration data (BCD)
- The HDD/SSD with the OS installed is not connected
Related posts:
- Here Are 5 Perfect Solutions to Missing Operating System
- [SOLVED] Operating System Not Found Error – How To Recover Data
Fix 1: Perform a Windows Startup Repair
First, you can try to perform a Windows Startup repair to fix the “an operating system wasn’t found” issue. Startup repair is an automated diagnostic and repair tool available from the Windows installation CD that can be used to find and fix some common issues.
Before using this method, you need to prepare a Bootable USB installation ready. To create it, you can refer to this post – How to Create Bootable USB from ISO Win10/11 for Clean Install.
Step 1: Now, you need to boot the PC from the USB drive to enter the Windows Recovery Environment.
Step 2: Press any key when the Press any key to boot from CD or DVD message appears on the screen.
Step 3: Select your language preferences in the Windows Setup interface, and click the Next button to continue
Step 4: In the next step, choose Repair your computer instead of clicking the Install now button.
Step 5: Click Troubleshoot > Advanced options > Startup Repair.
Fix 2: Configure and Repair the Boot Files
If the above method doesn’t help fix “an operating system wasn’t found” in Windows 11, you can consider configuring and repairing the boot files. The Windows bootloader on your MBR disk may be damaged.
Step 1: Connect the Windows boot media to the computer and boot from it.
Step 2: Then, choose your language, time, currency, and your keyboard input method and click Next.
Step 3: At the next screen simultaneously press the Shift + F10 keys to open the Command Prompt application.
Step 4: Find out whether your disk is set to GUID Partition Table (GPT) or Master Boot Record (MBR).
- In Command Prompt, type diskpart and press Enter.
- Type list disk and press Enter.
- Look for your disk and see if the GPT column has an asterisk (*) – this will indicate the disk is GPT. If no asterisk is found, then the disk is set as MBR.
- Type exit and press Enter.
Step 5: Repair the disk. You need to go to the corresponding part based on your disk’s type.
If the type is MBR:
1. Type dir a: and press Enter.
If drive A: is found and a directory is displayed, check for the \Windows folder in the directory. If it is there, that is the System drive. Skip to step 2.
If the drive is not found or it doesn’t contain the \Windows folder, type dir b: and press Enter. Continue through the alphabet until the drive with the \Windows folder is found, but skip the X: drive.
2. Once it is found, type :bcdboot C:\Windows /S C:
In this case, C is the drive where the Windows folder was found. If the Windows folder is on a different drive, use that drive letter instead of C.
3. Type diskpart and press Enter.
4. Type list disk and press Enter.
5. Type select disk C and press Enter.
6. Type list volume and press Enter.
7. Type select volume C and press Enter.
8. Type active and press Enter.
You should get a confirmation that the volume has been successfully set as active.
9. Type exit and press Enter.
10. Reboot the device – you can do this quickly from the command prompt by typing: shutdown -f -r -t 00 and press Enter.
If the type is GPT:
1. Type dir a: and press Enter.
If drive A: is found and a directory is displayed, check for the \Windows folder in the directory. If it is there, that is the System Drive. Skip to step 2.
If the drive is not found or it doesn’t contain the \Windows folder, type dir b: and press Enter. Continue through the alphabet until the drive with the \Windows folder is found, but skip the X: drive.
2. Type diskpart and press Enter.
3. Type list disk and press Enter.
4. Type select disk C and press Enter.
In this case, C is the drive where the Windows folder was found. If the Windows folder is on a different drive, use that drive letter instead of C.
5. Type list part and press Enter.
Look for the partition labeled as System. Once it is found, assign the letter R to the partition. If the letter R is already taken, you can choose any unassigned letter. To assign the letter type assign letter=r: and press Enter.
6. Type the following command and press Enter after each line:
- cd /d r:\EFI\Microsoft\Boot\
- ren BCD BCD.bak
- bcdboot c:\Windows /l en-us /s m: /f UEFI
In this part, we will show you how to fix the master boot record if you don’t have the Windows installation CD/DVD. To fix MBR Windows 10 without CD, you need the help of an MBR repair tool. Thus, the MBR repair software – MiniTool Partition Wizard is strongly recommended.
MiniTool Partition Wizard can help you to fix MBR with ease on Windows 7/8/8.1/10/11, just requiring a few clicks. Now, you can get MiniTool Partition Wizard immediately.
MiniTool Partition Wizard DemoClick to Download100%Clean & Safe
Step 1: Install MiniTool Partition Wizard on a normal computer.
Tips:
Tip: If you are running Windows 11, you need to create the bootable media on a normal computer that is also running Windows 11.
Step 2: Launch it to enter its main interface.
Step 3: Click the Bootable Media feature which can help you to boot your computer.
Step 4: Choose WinPE-based media with MiniTool plug-in. Then, choose the media destination. You just need to wait for the creation process to finish.
Step 5: Connect the bootable media to your computer that meets the “an operating system wasn’t found” issue.
Step 6: Change BIOS order and boot the computer from the MiniTool bootable media.
Step 7: Enter MiniTool Recovery Environment. Select the system disk and right-click it to choose Rebuild MBR.
Step 8: Click Apply to confirm the changes. After you have finished all steps, you can reboot your computer to check whether your computer can boot normally.
Fix 4: Reinstall the Windows
The last method for you to fix the “an operating system wasn’t found. Try disconnecting any drives that don’t contain an operating system” issue is reinstalling the Windows.
Tips:
Tip: We strongly recommend that you should back up your important data in disk C before making this kind of this huge change to your PC since it may cause data loss. To do that, you can try the file backup program – MiniTool ShadowMaker.
MiniTool ShadowMaker TrialClick to Download100%Clean & Safe
Step 1: Create Microsoft’s media creation tool or Windows 11 iSO file on any working computer.
Step 2: Insert the Windows 11 USB drive into the PC that meets the “an operating system wasn’t found” issue.
Step 3: Boot the PC and enter its BIOS menu to set the PC to boot from the USB.
Step 4: When the Windows Setup screen appears, choose your language and keyboard. Then, click Next.
Step 5: On the next page, click Install Now.
Step 6: On the Activate Windows page, click I don’t have a product key.
Step 7: Choose your Windows 11 edition and click Next.
Step 8: Accept the Microsoft software license, and then click Next.
Step 9: Choose which type of installation you want. You can choose the Upgrade option or the Custom: Install Windows only (advanced) option.
Step 10: Choose the drive partition where you want to install Windows 11.
Situation A: If you only have a new drive connected, you will see a Drive 0 Unallocated Space listed there. To install Windows 11 on a new hard drive, just select it and click Next.
Situation B: If you have got more than one hard drive connected to your PC, you’ll be shown a screen with several drives called Drive 0, Drive 1, etc. And if a drive is already partitioned, you will see Drive 0 Partition 1, Drive 0 Partition 2, Drive 0 Unallocated Space, etc.
In Situation B, you have 2 options, which are to install Windows 11 on the original system partition or to delete all partitions (by selecting each one and clicking the Delete option). This will erase all data on the partitions, so double-check that you’re deleting partitions from the correct drive and make sure you have already backed up everything you need.
Step 11: Just follow the remaining instructions on the screen.
Back up Your System After Fixing the Issue
What should you do after fixing the annoying issue? It’s highly recommended to back up your system to restore your system when it crashes. Here is a piece of professional backup software – MiniTool ShadowMaker for you to do that.
MiniTool ShadowMaker enables you to back up files and keep them safe from an unbootable computer. Besides backing up files or folders, it can also back up disks, partitions, and even the operating system. It can also help you clone the OS from HDD to SSD without data loss.
Now, download MiniTool ShadowMaker Trial from the following button or choose to purchase an advanced edition.
MiniTool ShadowMaker TrialClick to Download100%Clean & Safe
Step 1: After downloading and installing MiniTool ShadowMaker, launch it.
Step 2: Go to the Backup tab and you can find that system partitions have been selected by default.
Step 3: Then, click the DESTINATION part to choose a location to store the system image file.
Step 4: At last, click the Back Up Now button to start the backup task right now.
Bottom Line
In conclusion, this article focuses on how to fix the “an operating system wasn’t found. Try disconnecting any drives that don’t contain an operating system. Press Ctrl+Alt+Del to restart” issue. In addition, if you have any problem with MiniTool ShadowMaker, you can feel free to contact us via .