Windows 10: Windows 10 update corrupted dual boot options

When I first installed the Win 10 Preview, it set up a dual boot (actually triple boot, 3 OS's - Win 7, Win 8.1 and Win 10). One of the Win 10 updates corrupted it. I've tried to fix it by booting with all 3 OS install discs and running "bootrec.exe".

Bootrec.exe /rebuildbcd returns "Total identified windows installations 0"
Bootrec.exe/scanos lists all 3 OS'

Originally, I had a dual boot with Win 7/Win 8.1 until I installed the Win 10 Preview.

I no longer get boot options. On a power on or restart it will either boot directly to Win 10 Preview or to Win 7. I have to enter the BIOS and select which OS I want.

Jack

:)

 

I have Dual Booting Windows 7 Ultimate & Windows 8.1 Pro, Is upgrading my windows 8.1 Pro to Windows 10 will erase Windows 7 ?

I already reserved for windows 10 upgrade in my windows 8.1 pc. But as i have dual boot Windows 7 Ultimate & Windows 8.1 Pro, am worried if i update windows 8.1 to windows 10 , my windows 7 might get corrupted or unable to start after my windows 8.1 completed
to update wndows 10. Can anybody explain this ?? If it is safe to upgrade to windows 10 in dual boot desktop pc ??

 

How do I restore dual boot capability after Windows 10 clean install removed it

My computer was dual-boot with Windows 7 boot partitions on two separate drives. After upgrading to Windows 10, the dual boot provision worked fine. However after a clean install of Windows 10, dual-boot capability is no longer available. The boot partition
for the remaining Windows 7 syBistem is intact. Only the dual boot option is gone.

I tried the changing the default operating system under System Properties/Advanced/Startup and Recovery, but the only choice is Windows 10. Windows 7 isn't a option. I'm guessing that the clean Windows 10 install wiped out access to the dual-boot menu.

Thanks.

Bill

 

I had the same thing once.
Try holding Shift then press Restart, on the blue screen choose 'Change Defaults', the 'Timeout' entry might be 0
Change it back to 30 seconds or whatever.

 

"Shift then Restart" when or where?

I can check the timeout setting in msconfig.

 

Bring up Power Menu, hold Shift before pressing Restart.
For some reason it doesn't matter what's listed in msconfig.
(might not be the problem but it's worth a shot)

 

Thanks for the timeout fix. It was set to 0 in the primary system's "msconfig" for the OS boot selection. Setting it back to 30 seconds fixed the problem.

Jack

 

Yep get used to that one major updates 10 will always do that :/

 

I dual boot and so far it hasn't happened to me. *Smile Good info to have in case it ever does happen though.