Prologue: Apple et al recommend you “install new OS’s from USB, not DVD – USB is faster”, but I’ve never bothered before. However, there appears to be a major defect in most Apple iMacs, where the DVD drives fail after only a dozen or so uses (google it and there’s depressingly-long forum threads of people reporting the same problem). When this hit my iMac, I was forced to explore the USB alternatives…<\/p>\n
With the arrival of Windows 8, much of what we see on the web about “installing windows” or “booting windows” is wrong — including Apple’s own Bootcamp (currently: almost a year out of date, badly broken, and Apple hasn’t announced a fix. Sigh).<\/p>\n
Allegedly (confirmed by direct experience, but I’m no expert on this) – Windows 7 (and previous versions) used “MBR” booting. Intel Macs use the more modern “GPT” booting – and Windows 8 has finally dropped backwards compatibility, and uses GPT too.<\/p>\n
So, as of 2013: there is nothing “special” needed to make a Mac boot in Windows 8<\/p>\n
In fact, if you try to, Windows 8 install WILL FAIL because it doesn’t support the old MBR booting any more (it even produces a clear, helpful error message explaining why)…<\/p>\n
For power-users who know what they’re doing, this stack-exchange answer gives good step-by-step instructions<\/a> (with explanations!) on how to “un-break” a broken boot setup on Mac. Worth bookmarking (I used it to fix one of my machines).<\/p>\n NB: all the tools they use in that answer are pre-installed with the Mac and have “man” docs – type “man (command name)” in Terminal to read them.<\/p>\n NB: you can run these tools straight away, but they will probably refuse to “save changes” because you’re using the disk they’re trying to change (mentioned in the link above). You’ll need to boot into a special “repair mode” – see below:<\/p>\n NB: if you mis-type the instructions on that page, you probably will wipe your hard disk. Don’t try this while tired\/drunk\/etc – or at least take a full backup of your computer first!<\/p>\n The web is plagued with technically unskilled “journalists” who write articles about “make a USB boot disk for OS X”, and all they do is copy\/paste Apple’s own instructions on how to INSTALL OS X (and then they claim credit for it).<\/p>\n The OS X installer requires a 4GB – or, if you’re unlucky, an 8GB – USB key. That’s 8x what you actually need.<\/p>\n It is faster, easier, and safer to use Apple’s own “Make an OS X Bootable USB key” app<\/a>, which works on any USB drive that’s 1 GB or larger.<\/p>\n You can even create the USB key without downloading the special app<\/a> – although it requires more fiddling (I recommend: download the app. It’s small and trivial to use).<\/p>\n NB: if you own a mac, make one of these now. Do something useful with those crappy 1GB USB keys you have gathering dust on the shelf!<\/p>\n Because those USB boot disks are so massively valuable, Apple now includes a hidden one on your hard disk too, so that you can boot into that and “fix” your main OS X even if you don’t have a USB drive.<\/p>\nAn OS X “emergency boot USB drive” is only 1GB<\/h4>\n
OS X has an Emergency Partition by default – but you can’t use it<\/h4>\n