Virtualbox 4.2 error booting live partition

[Jim.Rather]

I dual boot Windows 7 and Ubuntu 12.04. I have configured Virtualbox when I am running Ubuntu 12.04 to boot my live Windows 7 partition. After installing 4.2 I am unable to boot my live Windows 7 partition. I tried re-creating my settings for the Windows 7 VM but that did not solve the problem. Wondering if there is something in the 4.2 version that prevents this or if anybody else is doing something similar and has it working with 4.2. I have reinstalled 4.1 and everything still works, so it is something specific with 4.2. Will try troubleshooting later, at the moment need to use my system. I have had this configuration working for the past couple of versions of Ubuntu and Virtualbox so I am unsure of what may have changed.

[mpack]

Have you seen the Windows 7 in both VM and Native howto? For some reason the author has added "in VBox 3.x" to the title, though I don't offhand see anything in it that will not work in v4.

ps. Moving this topic to "Windows Guests".

[Jim.Rather]

While troubleshooting different settings, I found one that prevented my VM from booting. Prior to this version, I had "Enable Nesting Paging" enabled. Unchecking it lets me boot my live partition (albeit it is much slower). The error I was getting was -1012 VERR_INVALID_RPL. I have looked it up in the err.h and it looks like it has something to do with an incorrect privilege level somewhere. Not sure how to correct this or if this is a new change going forward in Virtual Box.