By AOMEI / Last Updated June 21, 2019

Required device is inaccessible

Have you ever encountered this problem? When you turn on your computer, the computer that was working normally suddenly shows a blue screen with the following error message: “Your PC needs to be repaired. A required device isn't connected or cannot be accessed 0xc00000f”.

Required Device Inaccessible

After using the methods recommended in the lower left corner, you can find: Enter doesn’t work, F8 doesn’t work, F9 goes to Automatic Repair but nothing worked. Your computer will be stuck on this page and refuses to boot. There are multiple reasons for this issue like invalid configuration data, improper computer shutdown, and corrupted OS disk, etc.

No matter what the reason is, you should solve this problem immediately. How to fix required device isn’t connected or cannot be accessed? Read on please and your problem will be solved soon.

Top two ways to fix required device isn’t connected or cannot be accessed

Here are two simple but proven ways to fix the problem that a required device isn’t connected or cannot be accessed in Windows 10. You can choose one that suits you best.

Method 1. Run an automatic Startup Repair

Step 1. Start your PC, press Power button for 5 - 10 seconds when the manufacturers logo disappears and Windows is about to load. Then repeat this action.

Step 2. Windows will automatically enter the Recovery Environment when you turn on your computer for the third time. Click Advanced options in the recovery screen.

Advanced Options

Step 3. Click Troubleshoot on the Choose an option screen.

Step 4. Click Advanced options.

Step 5. Click Startup repair. Then follow the onscreen instruction.

If the Windows 10 Startup Repair not working, you can try next method to fix the problem of the boot selection failed - a required device is inaccessible.

Method 2. Run a Startup Repair via Command Prompt

Before you do, you need a Windows installation DVD. If you don’t have, you can create a bootable disc on a well-functioning PC. Press F8 while booting the system to go into the Windows Recovery menu.

Step 1. Go Troubleshoot > Advanced Options > Command Prompt.

Commant Prompt

Step 2. In command prompt, type the following commands in order:

  • bootrec /fixmbr

  • bootrec /fixboot

  • bootrec /scanos

Tips: If you receive that "Total identified Windows installations = 0", you can type the following commands:

  • bcdedit /export C:\bcdbackup

  • C:

  • cd boot

  • attrib bcd -s -h –r

  • ren C:\boot\bcd bcd.old

Step 3. Rebuild Boot Configuration Data by typing the command below:

bootrec /rebuildbcd

Step 4. Press A to add installation to boot list and then press Enter.

Add Installation

Step 5. Close system and restart your computer.

However, some people complaint that these two means are too time consuming. In addition to this, a little careless will cause data loss because of complex operating steps. Fortunately, you can do a system backup to avoid data loss. If the two ways mentioned above don’t work, you also can restore system to the normal working time via the system backup image.

Freeware to backup system in Windows 10/8/7

If you are looking for a Windows backup utility, AOMEI Backupper Standard is recommended. With its easy steps and simple interface, you can create a system image with a few clicks. Windows 10/8.1/8/7/Vista/XP are supported.

With its scheduled backup, you can keep your data up to date. What’s more, incremental copy and differential copy in this freeware can help you backup changes only. Don’t hesitate to download this freeware! Let's see how it works.

Step 1. Install and launch this freeware.


Step 2. Click Backup and System Backup subsequently.

System Backup

Step 3. Change the Take Name as you like. The required system partitions are selected by default in Step 1. Select the destination path (G:\) in Step 2. Then click Start Backup.

Start Backup

Step 4. When the System Backup Progress is completed, you can click Finish.



  • Backup Options: you can comment, compress or split the image file here. Enable encryption for backups (supported by AOMEI Backupper Professional) under General tab can help you create a backup encryption.

  • Schedule: works well to setup an auto backup to run Daily, Weekly, Monthly, Event triggers, USB plug in or Real-time Sync. The last three options require you to upgrade to the advanced version.

  • Scheme: it will delete older backups automatically (in paid version).

  • Check backup integrity on completion: the program will check the data integrity of the backup after backing up system.

  • After backing up, you can select Shut down PC, Restart PC, Hibernate or Sleep at Step 4.

  • If you want to restore system later, you can go Home >the System Backup task > Restore.


The two methods mentioned in this article can help you fix required device isn’t connected or cannot be accessed. Remember that developing a good habit of backing up is fairly important for disaster recovery. For backup utility, AOMEI Backupper Standard can be your ideal choice.