Win8 into Safe mode without the Last Known Good configuration option?

after a lot of users install the WIN8 system, go into safe mode and find that there is no last Known Good configuration option, how do you turn on the last Known Good Configuration option ?

How to turn on the last Known Good Configuration option:

1, in the "Run" dialog box, enter "regedit" Open Registry Editor;

2, sequentially expand to "Hkey_local_machinesystemcurrentcontrolsetcontrolsessionmanagerconfigurationmanager", create a "LastKnownGood "The new term;

3, click the new item, select Edit, choose New, DWORD value, create a value named "Enabled", double-click to modify its data to "1";

4, positioning to "Hkey_local_machinesystemcurrentcontrolsetcontrolsessionmanagerconfigurationmanager", a new "DWORD value" for " Backupcount value, double-click to modify its data to "2". Close Registry Editor after confirming the error;

5, return to the desktop, open the command prompt, enter Bcdedit/set "{bootmgr}" Displaybootmenu Yes, return to the "Operation completed successfully" prompt, then type Bcdedit/set "{current}" Bootmenupolicy Legacy execution;

6, restart the computer, when the system starts to press the F8 key to switch to the advanced startup options, you can see the "Last Known Good Configuration" option.