Upgrade to Windows 10 caused Windows 7 x32 unable to boot.

I had a triple boot Windows 7 x64, Windows 7 x32 and Windows XP x32. I did upgrade Windows 7 x64 to Windows 10 while retaining all installed applicatiopns. The end result is both Windows 7 x32 and Windows XP x32 are unbootable.

I did not know Windows 10 is not designed to upgrade from Windows 7 in multiboot enviroment. Still, upgrade seems to be the only way to retain the same drive letter assignments used in all installed systems. The multiboot solution grew from Windows 9x to Windows 2000, XP, 7 x32, and finaly 7 x64, while loosing Windows 9x and 2000 on the way.

Now the question is, is it possible to regain ability to boot Windows XP and Windows 7 x32.

Or perhaps I have to revert to old XP, 7 x32 and 7 x64 layout, and then to add Windows 10 as fourth option. If it is possible to launch Windows 10 setup from Windows 7 x64 it could be possible to retain drive letter assignments used in old Windows 7 x64.

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The boot menu seems to be working, fine. But both Windows 7 x32 and XP are hanging during the boot.

The BCD database seems to be different just for Windows 10 entry. The Windows 7 x32 and XP records are exactly the same, as they were before upgrade to Windows 10.

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For some reason everything started to work correctly. Not sure where the cause was. I did change the boot menu from GUI to text mode i the process. Perhaps it made the difference.

Edited October 22, 2025Oct 22 by Sfor