I want to upgrade to Yosemite but before I do, I need to know if the upgrading process will require I reinstall all my apps once the upgrade is done. I am in the middle of a lot of work and don't have time to re-install every app again such as Photoshop, Lightroom and a host of other phoography related software.

Thanks for your help.


  • Finish the work first. Better safe than sorry, in case of compatibility issues of any kind. You should have no problems, on paper, but this site is full of people who did,
    – Tetsujin
    Nov 5 '14 at 21:06
  • 2
    You don't mention using Time Machine. If you're not using it now, start immediately, even if you wait until later to upgrade to Yosemite. When you finally upgrade, you should make sure beforehand that versions of the crucial apps you're using for your work are compatible.
    – IconDaemon
    Nov 5 '14 at 22:33

No, it won't - Since at least Snow Leopard, the upgrade is just done over the top of the original install. The core of the system doesn't change much these days, it's more about adding features/apps.

I'd recommend backing your work up anyway (even if you don't upgrade!) and if you have an urgent deadline, upgrade afterwards... base the time on the assumption you'll have to re-install, simply because installations can and do (fairly rarely) go wrong.

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