virtualbox.org

I have an old MacBook running 10.7 Lion. I'd like to run VirtualBox on it for a project. My question is what is the last version of VirtualBox that will run on a 10.7 Lion host? I think it may be the 4.3 branch, therefore version 4.3.40, but I haven't been able to find a definitive answer. The current version of VirtualBox requires 10.12 minimum.

That's funny, they removed that information from the 6.0.x User Manual... But it's still in the older 5.2.x ones, like the 5.2.26 User Manual at chapter 1.4 Supported host operating systems, the footnote:

1. Support for 64-bit Windows was added with VirtualBox 1.5. Support for Windows XP was removed with VirtualBox 5.0. Support for Windows Vista was removed with VirtualBox 5.2.
2. Preliminary Mac OS X support (beta stage) was added with VirtualBox 1.4, full support with 1.6. Mac OS X 10.4 (Tiger) support was removed with VirtualBox 3.1. Support for Mac OS X 10.7 (Lion) and earlier was removed with VirtualBox 5.0. Support for Mac OS X 10.8 (Mountain Lion) was removed with VirtualBox 5.1. Support for Mac OS X 10.9 (Mavericks) was removed with VirtualBox 5.2.

So, yeah, 4.3.40 (unsupported) is your only "official" option at the moment.

Having said that, 5.2 was supposed to have removed support for 10.9. Well, guess what? I'm running the latest 6.0.5 test builds and 6.0.97 development builds on my 10.9.5 host, with no apparent problems. But I'm not going to start filing tickets against it any time soon...