Boot Windows 7 on 2015 MBP using Refind?

[James Lee]

I realize that Apple ended Windows 7 support for 2015 MBP, but I'm trying to see if I can get 2015 MBP to run Windows 7.
I need to use some programs that only run on Windows 7, and I can't use Vmware because they requires a lot of resources (cpu and memory).
Anyways, here are the steps I took.
1. I created a Bootcamp partition using bootcamp assistant using Windows 10 image.
2. I finished Windows 10 installation until I got a desktop.
3. I created a VM using vmware, and I set it to use physical disk.
4. I started the installation process for Windows 7 using the VM and formatted the partition with Windows 10during the Windows 7 setup.
5. When the set up finished copying files and counting down to restart, I shutdown the VM.
6. I loaded the refind and rebooted.
7. I got two Windows options efi and bootcamp.
Here's the problem I ran into.
If I choose bootcamp, it complains that legacy loader is missing.
If I choose efi, it just goes black.
Any idea on how I can at least get it to boot?
Thanks!

[Roderick W. Smith]

First, a caveat: I've never used Boot Camp. I have installed OSes in BIOS mode on a Mac, but not often, and not using Apple's Boot Camp tools per se. I've also never installed Windows on a Mac, in any mode. Thus, I don't have a good hands-on understanding of what the conventional Windows installation process is on a Mac.

Second, any installation involving GPT with a hybrid MBR, as is necessary for a BIOS-mode install on a Mac, is risky. Hybrid MBRs, which Apple's Boot Camp sets up for Windows 7 installations, are ugly and dangerous hacks. IMHO, Apple was irresponsible to rely on them. Unfortunately, it's next to impossible to get Windows 7 booting in EFI mode on a Mac, so you're pretty much stuck with a hybrid MBR if you must run Windows 7. Given the problems of a hybrid MBR, though, I recommend you at least consider using Windows 8 or Windows 10 instead of Windows 7, even if you prefer Windows 7, since you can usually install Windows 8 or later in EFI mode. Alternatively, you could read and ask questions on this thread, in which EFI-mode Windows 7 installs are discussed. It's very long and hasn't seen activity in years, but AFAIK it's the best resource for this topic.

That said, If you really want Windows 7 in BIOS/CSM/legacy mode, you might try this:

1. Back up your important data. There is a risk that one or another step in this procedure will result in catastrophic data loss.
2. Create partitions for Windows using Disk Utility or some other tool in OS X (or using a live Linux disk -- but not using a Windows tool!). Note that the Linux GParted tool can shrink HFS+ partitions, if you need to do that. It shouldn't matter what filesystems the partitions for Windows use, although using NTFS might simplify things just a bit, and FAT would be my second choice. It's important that you fully understand what partitions Windows 7 wants so that you can create them ahead of time. (Sorry, I'm not an expert on that detail.)
3. In OS X or a live Linux disk, run my gdisk utility on the disk. Use it to create a hybrid MBR that contains your to-be-NTFS partition(s) for Windows. Be sure to give them MBR type codes of 0x07.
4. Launch the Windows 7 installer in BIOS/CSM/legacy mode. rEFInd should be able to launch it, if rEFInd is already installed. If the installer complains about the MBR partition table, then it's running in EFI mode, which most likely wouldn't work.
5. Install Windows normally. It should "see" the partition(s) you've created for it and enable you to install to them.
6. When you're done, run gdisk again, and use its v option to check the partition table's integrity. If it reports errors, correct them immediately. This may involve anything from a minor tweak to completely re-installing everything. If no problems are reported, then you at least know you haven't trashed everything.

At this point, you should have a dual-boot of OS X and Windows from rEFInd. It may still be necessary to install additional drivers for Windows 7, though. (In fact, it's conceivable you'll need to track down an extra driver or two to be fed to Windows during the installation process.)