[Fixed] Windows 10 Won’t Boot after Partition Resize

Scenario

“I got a new laptop and resized my C drive from 930 GB to 530 GB using disk management. Because it can no longer be partitioned, I tried third-party software to partition the C drive and reduce its size to 130 GB. Windows is unable to boot after restarting the laptop. Please tell me how to BOOT the windows?”

Possible reasons for boot failure after resize disk Windows 10

Resizing a partition is normal partition management work. During daily use, users might need to create, delete, and extend partitions to customize their disks. Especially, the C drive, if the C drive is full or damaged, the computer will be affected a lot. Thus, many users will resize the C drive, which may cause some problems, and one of all symptoms is boot failure.

C drive is also called a system drive because it stores all OS files. Resize C drive in an incorrect way might beget:

• The BOOTMGR files corrupted
• MBR part damaged
• OS file loss
…

And all these can be the reason why your Windows 10 won’t boot after partition resizing.

3 ways to fix Windows 10 won’t boot after partition resize

To fix the boot error, here, we’ll show you 3 ways. The first employs Windows Startup Repair, the second use CMD and the third, a third-party tool.

Way 1. Run Windows Startup Repair

▶ Note: You’ll need a Windows installation USB or disc to boot your PC.

Step 1. Shut down your computer and unplug all peripherals.

Step 2. Insert the Windows installation tool and turn on your computer. You may need to enter the computer’s BIOS to change the boot sequence so that you can boot from the Windows installation tool.

Step 3. When it gives you the message “Press any key to boot from CD or DVD...”, press any key to boot your computer.

Step 4. When the Windows install screen shows up, and click "Repair your computer" in the lower-left corner.

Step 5. Click Troubleshoot -> Advanced options -> Startup Repair. The Windows will scan your new drive and automatically detect that the boot sector has been damaged or is missing and will apply the appropriate fixes.

Unplug the Windows install media and reboot your computer to check if the problem is solved or not.

Way 2. Use Command Prompt

If Startup Repair can’t solve the issue, let’s try to fix the bootrec error to solve the problem via Command Prompt.

Step 1. Boot your PC as the steps in Way 1.

Step 2. After you click: Repair my computer”, click Troubleshoot -> Advanced options -> Command Prompt.

Step 3. In the CMD window, please type the following commands and press “Enter” after each:

• bootrec /fixmbr
• bootrec /fixboot
• bootrec /scanos
• bootrec /rebuildbcd

Then you can try to reboot your computer.

Way 3. Employ third-party tool to rebuild MBR

If both first two methods can’t help you, well, you can try AOMEI Partition Assistant Standard, a free disk and partition manager for Windows 11/10/8/8.1/7/XP users.

This tool has a “Rebuild MBR” feature for users to rebuild damaged MBR on the disk with user-friendly operation. You can fix the damaged MBR without Windows installation USB.

Step 1. Insert the USB drive to the working Windows PC and make sure it can be detected. Launch AOMEI Partition Assistant Standard. Click "Create Bootable Media" under "Tools" to create a bootable USB drive.

Step 2. Unplug the USB drive from the working PC and insert it into your unbootable Windows. Get into BIOS to change the boot order so that it can boot from the bootable USB drive you created with AOMEI Partition Assistant Standard.

Step 3. When it boots from the USB drive, you’ll see the main interface of AOMEI Partition Assistant Standard. Select the cloned drive, right-click it and select “Rebuild MBR”.

Step 4. Set the type of MBR for the current OS, and click OK.

Step 5. When you back to the main interface, click “Apply” -> “Proceed”.

After a while, when it completes, unplug the USB drive and restart your computer. It would be worked.

To sum up

Windows 10 won’t boot after partition resize? Don’t worry. Try 3 ways in the guide one by one. AOMEI Partition Assistant is a multifunctional tool, upgrade to the Professional Edition, and then you can enjoy more convenient functions such as converting system disk to GPT/MBR without data loss, OS migration, allocating free space to the C drive, etc.

What’s more, it also has the Server Edition for Windows Server 2025/2022/2019/2016/2012(R2)/2008(R2)/2003 user to manage their Server devices and the Unlimited Edition for business users.