Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Does OSX Lion break Bootcamp with Windows 7 installed?

I've been looking around online and can't seem to find a definitive answer on this. I'm considering upgrading to Lion, but I'm worried that it might wipe out my Windows bootcamp. Does anyone know whether Lion breaks bootcamp (I have Bootcamp 3.2 installed).

share|improve this question
anecdotal: a friend of mine has successfully upgraded to Lion with a windows 7 partition without trouble, but see @digitxp answer for best results. – DTest Aug 10 '11 at 14:57
I successfully upgraded without any hiccups. Parallels 6 (or whatever the one NOT built for Lion was) still works great with my bootcamp partition. Thanks! – kalaracey Sep 12 '11 at 0:43
up vote 2 down vote accepted

There are three possible outcomes involving your Boot Camp'd Windows 7 when upgrading Lion:

  1. It completes successfully and works perfectly without any tinkering.
  2. It completes, but you need to download updates and tinker a little.
  3. It deletes your entire Boot Camp partition.

I'd say the most likely situation is 2, but (of course) the Lion installer will try as hard as it can to produce 1.

However, it's still just a computer and thus it's a good idea to assume the worst. Back up your Windows 7 partition to somewhere safe before upgrading.

share|improve this answer

I have moved to Lion coupled with Parallels 7 and would like to give a bit of warning if all goes well in the migration.

Do NOT modify the disk partions using OS X disk utility. Any change to the partition table can (and most likely will) cause your Windows partition to be destroyed both the VM, if you are using Parallels, and Boot Camp.

I have spent many hours reinstalling Windows because of this very issue. So as digitxp said, expect the worse. I just hope to help highlight what the worst could be.

Not sure why I did not include this in my answer before. Regarding modifying the disk partions. If you change them before running Boot Camp, Boot Camp will fail and make you create a single partition for OS X before you can continue. In addition if you change the partitions after installing Windows, it will destroy the Windows partition. The only way that I have seen to create multiple partitions with Lion and Boot Camp can be found here at

share|improve this answer
When do you advise NOT modifying the partition table? After or Before? I didn't touch anything and was fine. Thanks for your input. – kalaracey Sep 12 '11 at 0:44
@kalaracey: If you modify the partions after installing Windows you're sunk. – Adam Lewis Sep 12 '11 at 0:53

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .