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I'm installing Mtn Lion and I'm wondering what will happen if I format my disk as ExFat and install Mountain Lion on it that way.

Any major advantages or disadvantages to doing this?

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If you are already doing a format just try it – Ramhound Sep 5 '12 at 17:43
Well the install takes an hour, if this is a bad idea (down the road) I'd like to know! – bobobobo Sep 5 '12 at 18:00
up vote 3 down vote accepted

Nope, OS X can only boot from Mac OS Extended (aka HFS+) and its variants (journaled, encrypted, and/or case sensitive). I don't have anything to test with here, but I'd be amazed if the installer even let you try installing it on ExFAT.

BTW, this isn't just a matter of "Apple hasn't bothered to support it"; OS X depends strongly on the Posix file permissions model, and ExFAT doesn't support that (just ACL permissions). It would take a lot of work to make OS X work on a volume where you can't have setuid files.

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