CentOS 7 with Windows dual system lost Windows startup item and default startup item modification

1. Why Windows Startup Items disappear:

After installing the Win7, 8/10 system +centos7 dual system, the MBR (Main Boot Record) is overwritten by default to GRUB2, and the default CentOS7 does not recognize the NTFS partition of Windows, so there is no Windows system in the startup item.

2. Solution:

(1) First to ensure that Linux can be networked (judging method can ping the network, see if Unicom)

If there is no ping pass, the workaround is as follows:

Root Access directory: cd/etc/sysconfig/network-scripts/

Use the LS command to view the NIC configuration file name (the NIC name looks like a random number in CENTOS7, so the NIC name of each machine is not the same)

Use Vim to edit the file: Vim ifcfg-eno16777

Then click "I" to enter the editing mode, the last line of Onboot=no, change to Onboot=yes;

Finally click "ESC" key, enter ": Wq" save to exit the file.

Restart Network: Service network restart

(Ping it again, you can ping it)

(2) Download Ntfs-3g:yum install Ntfs-3g-y

(3) Root user access, Vim/etc/grub.d/40_custom

In the last line join:

Menuentry = ' Windows7, 8/10 ' {

Set root= (hd0,1)

Chainloader +1 (there is a space between Chainloader and +1)

}

(4) Reset grub,root user execution: Grub2-mkconfig-o/boot/grub2/grub.cfg

(5) Restart: reboot

3. Modify the default startup item and start the read second time

Generally we are accustomed to the Windows system as the default startup item, and after installing the dual system default startup item is Linux, modify the method as follows:

(1) Root user editor: Vim/etc/default/grub

Then comment (start with ' # ') grub_default=saved, add grub_default= "Windows7, 8/10" on the next line, save and exit.

(2) The root user executes the following command: Grub2-mkconfig--output=/boot/grub2/grub.cfg

(3) The root user executes the following command: Vim/boot/grub2/grub.cfg

Change the time after "timeout" to the number of seconds you want to set, and then save the exit.

(4) Restart: reboot

4,linux system uninstall:

  When the Linux system is installed, perhaps someone would like to delete, (for example, I have a tool to expand the C-drive, after the expansion of the Linux system to find out, have to unload and then reload) someone will do this: right-click "My Computer" click "Manage", and then click " Disk Management "formatted the disk with the Linux system installed!" This is absolutely no way to do!!! (Important things to three exclamation points) because when you install the Linux dual system, the MBR (boot zone) to the Linux management, if the format will be the MBR to erase, so that your windows will not start properly! Then in the Windows System environment for the repair of the MBR, we use the tool is "Diskgenius" software, it looks like this, click on the disk "rebuild MBR" on it, then you can format Linux that hard disk, This will ensure that your windows will not be destroyed!

Done!!!

CentOS 7 with Windows dual system lost Windows startup item and default startup item modification