“Few days ago, I had accidentally marked Drive E active. My computer can’t boot. I really need a boot device. Could my system repair disc work as boot device? By the way I also have HP recovery DVDs.”Actually, you may have encountered this problem when using computer. This article will introduce you the solution to this issue.
When mentioning active partition, you should know what it refers to. The computer system boot partition must be active, that is to say, all files which are used to boot operating system are stored in the active partition. There must be only one partition on each hard drive which can be set as bootable partition or active partition.
If your boot partition is not active, operating system can’t boot. During the process of computer boot, BIOS will pass to Master Boot Record (MBR). Then MBR reads master partition table to find the active partition, and finally find Windows boot programs BOOTMGR and winload.exe to boot computer. If boot programs can’t be located, your computer is unbootable.
Therefore, if you accidentally marked drive E active, but drive E is not boot partition, “BOOTMGR is missing” will appear and system can’t boot. You must set active partition correctly.
If your computer can’t boot, you can use installation disc to boot computer. Once installation loads, select the language you want to use. Click “Command Prompt” in System Recovery Options window.
Then you need to type “diskpart” prompt to open diskpart command.
1. Type “list disk” and you will see all disks on your computer.
2. Then type “select disk n”. N represents disk number. You can select the disk in which OS installs.
3. Type “list partition”, and you can see all partitions on the target disk.
4. Then type “select partition n”. N means the partition number.
5. Type “inactive” or “active”. Here you need to set your E drive as inactive. And select system partition and set it active.
More operating details are as following screenshot.
Diskpart may be a little difficult to type prompts for you. Here a professional and powerful bootable partition manager is recommended to you, which is MiniTool Partition Wizard Bootable CD. You can use it to manage your partition and disk well. It is just an ISO file. You need to download this file and burn it to a CD/DVD or USB flash drive in another computer. Then after burning, you can boot computer via the bootable disc.
Here is the guidance about how to set system/boot partition active:
Step 1: Firstly boot computer from the bootable disc by setting boot from CD-ROM or USB flash drive in BIOS. Then you will see this interface.
Step 2: You will enter into MiniTool Partition Wizard main interface. You can see system reserved partition is inactive but partition 3(Drive E) is active. You need to click partition 3 and select “Set Inactive” from “Operations”.
Step 3: Then click system reserved partition, and select “Set Active”.
Step 4: At last, you need to click “Apply” to perform all operations.
Like that, with the help of MiniTool Partition Wizard Bootable CD, you can easily solve “accidentally marked drive E active” issue. Just try it.