How to Recover Accidentally Deleted Operating System in Windows 10

Jean updated on Sep 15, 2020 to Resource | How-to Articles


If you accidentally deleted Windows operating system on your computer, you won't be able to boot your computer normally and all the data on your PC become inaccessible. To recover your deleted operating system in Windows 10 and make your computer boot again, follow the guide below to get things done.

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 Windows 10 is supported

Accidentally Deleted Operating System in Windows 10

It's not easy to delete Windows operating system during our daily use and impossible to delete it if you are operating in Windows. However, the Windows operating system is not undeletable. Generally, there are several situations in which you may accidentally delete the operating system on your computer.

  • Accidentally delete OS in Windows Preinstallation Environment
  • Boot a computer via a bootable media and then delete the operating system by mistake
  • The computer has dual operating systems and you delete one of them after booting into another
  • You delete the operating system after system clone, OS reinstallation, system recovery, misoperation...

When the operating system is deleted, you can't boot your computer as expected and the files stored on your computer hard drive are inaccessible. To eliminate this annoying issue, you need to recover the deleted operating system and make your computer boot normally again. 

How to Recover Accidentally Deleted Operating System in Windows 10

Generally, deleting an operating system means deleting the whole system partition. Thus, you need a partition tool - EaseUS Partition Master to recover the deleted system partition. With the help of this tool, you can recover your deleted operating system in Windows 10 and boot your PC normally again via three procedures:

  • Create a bootable media with EaseUS Partition Master
  • Boot your computer from the bootable media and recover the system partition.
  • Afterward, you can add a boot option in BIOS/UEFI to boot Windows from your computer hard drive again. To get back your deleted OS:

Procedure 1. Create a Bootable Media with EaseUS Partition Master

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 Windows 10 is supported


Step 1: Prepare a disc or drive

To create a bootable disk of EaseUS Partition Master, you should prepare a storage media, like a USB drive, flash drive or a CD/DVD disc. Correctly connect the drive to a computer that can boot properly.

Launch EaseUS Partition Master, go to the "WinPE Creator" feature on the top. Click on it.

create easeus partition master bootable disk

Step 2: Create EaseUS Partition Master bootable drive

You can choose the USB or CD/DVD when the drive is available. However, if you do not have a storage device at hand, you can also save the ISO file to a local drive, and later burn it to a storage media. Once made the option, click "Proceed".

create easeus partition master bootable disk

You have created an EaseUS Partition Master WinPE bootable disk now. Connect the WinPE bootable disk you have made to the PC with the corrupted Windows system, restart the computer and go to BIOS/UEFI to change the boot sequence. Press "F2" (the BIOS key varies according to the computer manufacturer) when you start your PC. It will allow you to run EaseUS Partition Master and recover your system partition without Windows.

Before you start, there are things you need to identify.

If you see your original system partition shown as unallocated space in EaseUS Partition Master or RAW, you can recover the partition and the Windows operating system together with it following the steps below. If you see the system partition still exists but you cannot boot your computer. It's probably some Windows system files are deleted by mistake. In such a case, you can refer to the article about system boot issues (this article is related to other software but some of the solutions are universal) or create a bootable media with the hard drive recovery software - EaseUS Data Recovery Wizard, boot your computer from the device, recover your deleted Windows system files, and create a boot option in BIOS/UEFI to recover your operating system.

Procedure 2. Recover Deleted Operating System in Windows


Step 1: Launch EaseUS Partition Master on PC

Click on "Partition Recovery" at the top of the main window.

Run EaseUS Partition Master for partition recovery

Step 2: Select a hard disk to search for the lost partition(s)

Choose the hard drive disk or SSD where you lost partitions, and click "Scan".

Run EaseUS Partition Master for partition recovery

Step 3: Wait for the scanning process to complete.

This program will scan the whole disk with two modes - "Quick Scan" and "Deep Scan" to find all lost partitions and data for you.

  • Quick Scan will find your latest or recently deleted partition at a fast speed.
  • Deep Scan will scan and find more and earlier deleted partitions. 
  • If the Quick Scan doesn't find your lost partition, wait patiently till the Deep Scan completes.
Scan lost partitions

Step 4: Select and recover lost partitions

1. Select the lost partition, marked as "Deleted" with previous Labels, capacity etc, and click "Proceed" to continue.
2. Click "Recover Now" to confirm and restore the lost partition.

Scan lost partitions

3. Click the "Execute Operation" button and click "Apply" to restore lost partition.

Scan lost partitions

Procedure 3. Add a Boot Option

Adding a boot option in BIOS or UEFI boot mode is not easy to do. You can search for the guide on the Internet according to your boot mode and brand of your computer. Or you can directly contact our support team via live chat or telephone number provided below for remote assistance. In addition to creating the boot option, our support team can also help in other aspects like data recovery.

Do You Need Specialized Services for System Boot Issues?
EaseUS also provides 1-on-1 remote assistance to fix the boot issue. If the solution above does not work for you, please contact our professionals via Email or LiveChat in this page. To ensure our professional assistance work, you are suggested to connect the unbootable system drive to a healthy computer when getting connected with us.

The Bottom Line

Accidentally deleting operating system is quite rare but still exists. To reaccess the files on your computer and recover the deleted OS, you need to create a bootable media with partition recovery software, like EaseUS Partition Master, which is 100% secure, virus-free, and plug-in free. If you have any difficulty performing data recovery or adding a boot option, you are welcomed to ask help from our support team.

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Frequently Asked Questions

1. Why choose EaseUS Data Recovery Wizard?

"EaseUS Data Recovery Wizard is the best we've seen. It's far from perfect, partly because today's advanced disk technology makes data-recovery more difficult than it was with the simpler technology of the past, but it's fast and efficient..."PCMag

"The first thing you'll notice about EaseUS Data Recovery Wizard Pro is that its interface is very clear and uncluttered, with only a small collection of self-explanatory controls. You won't find lots of extra options hidden in a system of hidden menus, either; what you see really is what you get."techradar

"Recover lost files, even after deleting a partition or formatting your drive."Macworld

2. Why cannot I recover 2GB data for free?

It is recommended to check the version installed is Free or Trial because they are different versions.

Trial has data preview function but cannot save any files, while the Free version enables to recover 2 GB files. The default free space is 500 MB and you may share the product on social media to get another 1.5 GB.

3. Why cannot the recovered files be opened?

A file is saved as 2 parts on the storage device: directory info (which is comprised by file name, time stamp and size info, etc.) and data content.

If the files with original file names and folder structures cannot be opened, one possible reason is the corrupted directory info. There is still a chance to recover the data content with the RAW Recovery method in our software.

4. Why isn't it suggested to recover the files back to the original drive?

The storage structure of the lost files would be altered or damaged by any changes on the drive. If you save the recovered files back to the same drive, the original data structures and data content would be corrupted or overwritten, which causes permanent data loss. So you should prepare another disk to save the files.

5. How can I check whether my data is recoverable or not before purchase?

The Free version helps you save 2GB files to better verify the recovery quality of our product before purchase.

6. How long does it take to scan the drive?

It strongly depends on the capacity of your hard drive and the performance of your computer. As reference,most drive recoveries can be completed in around 10 to 12 hours for a 1-TB healthy hard drive in general conditions.

About Data Recovery Wizard

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