So, basically the same advice applies as with the upgrade to Yosemite: move /usr/local to somewhere like ~/local before upgrading, and move it back after.

It's worth mentioning that after the upgrade you might run into permissions problems: https://github.com/Homebrew/homebrew/blob/master/share/doc/h...

You might want to run `brew update` before updating, so `brew doctor` can help you troubleshoot issues afterwards.

hm, no worries at least on my machine.

I knew about /usr/local problem from Yosemite, though on El Capitan (same time as Yosemite, with /usr/local moved to ~/local) it was smooth as butter (I did not move /usr/local). All upgrade took about 30 minutes, and after it was done, I did sudo chown -R $(whoami):admin /usr/local and I was good to go.

Good advice, I plan on running a quick rsync:

rsync -rtvpl /usr/local ~/usr.local.backup

Does OS X place any of its own files in /usr/local?

I can't speak to El Capitan, but no Apple software has dropped anything in /usr/local that I've found in the last 3+ releases. I'm very confident El Capitan would continue that history.

A lot of other apps do put stuff there though (when I wish they'd keep it in their own bundle).

Even worse, a lot of other apps drop stuff into /usr/bin.

They can no longer drop stuff in /usr/bin as of El Capitan, though.

You can't even do it with root:

    [mason@IT-PC-MACPRO ~]$ sudo bash
    Password:
    [root@IT-PC-MACPRO ~]# touch /usr/bin/nope
    touch: /usr/bin/nope: Operation not permitted
    [root@IT-PC-MACPRO ~]# cat 'nope nope' >> /usr/bin/nope
    bash: /usr/bin/nope: Operation not permitted

I can't verify but that would be awful it did as `/usr/local` is meant to be exactly not that.

If you wipe the system then the time to set it up exactly like it was before is usually orders of magnitude larger than just waiting for the upgrade to move your brew installation out of /usr/local and back again. A better advice would be to just move the contents of your /usr/local to another directory and then move them back to /usr/local after the installation finishes.

I just ignored this and waited for the installer to do whatever it wanted. It took about 1 hour but everything went fine and I'm now up and running.

I upgraded to the gold master a while back on an iMac and didn't run into this problem. Do we know if it is different for the final release. Oh and a sidenote, my unix tools were not broken after this update. They typically are and need to be reinstalled

It gets stuck because it's moving every Homebrew app out of /usr/local, a known but painful issue.

I think the same applies to TeX distributions. It awfully slow for some reason, perhaps it double checks each file to avoid bit errors in system critical files?

Yeah, my Yosemite update over 3 because TeX has so many files that it moves one by one out and back of the texbin directory.

I believe it includes all the source, which is what consumes most of the time.

You need to move everything out of /usr/local into a temp location (I just dropped it into a folder in my home dir) and then after install, move it back.

I ran 'brew update' and 'brew upgrade' just prior to upgrading to El Capitan. After the upgrade I just had to change ownership on /usr/local back to myself, but everything else seems fine.

Ah, yes, I remember now that this happened with Yosemite too. I had to let the install finish over night. Thank you for the timely reminder.

I must be missing something, if you are going to do a wipe and fresh install why not go directly to el capitan?

If you do a full reinstall via cmd+r I'm unaware if it goes to El Capitan or the last installed version; obviously going direct would be the best approach.

Oh, I just make a USB drive capitan boot installer.

Another Homebrew user here, El Capitan installed without major issues and is running very smoothly IMHO. A difference might be that I haven't touched Homebrew in a while.

I've been running the betas and didn't have this issue. /usr/local was also fine other than fixing the permissions.

User with Homebrew here! No problems upgrading this time (took ~15 minutes), had ~2hr upgrade last time.

Mine was under a minute, but I'm not a big brew user --- just have a few key packages. Also, I'm on a Transcend SSD.

Really? That's awesome! I don't mind waiting but that always annoyed me.

Coming from Yosemite, you should clean you Mac with petrol. But seriously, Yosemite was such a mess, it felt like an old Windows installation where formatting is the only way to regain a decent performance. I'm glad I made a clean install with the GM 2 weeks ago. The system is way better than Yosemite (but still far from being as stable as Mountain Lion)

Sounds like cargo cult.

Whatever problems Yosemite had, they weren't caused because of "file accretion", nor would they remain after the OS is updated (as if it somehow reads old problematic files and goes back to its old buggy ways).

(That said, I had zero problems as a heavy dev+audio/video user of Yosemite, and zero too after updating to El Capitan GM -- with the exception of Cubase and NI audio units not working in Logic).

Wait, feeling that this update is better is OK, but I don't really understand how formatting could improve thing is such a significant way.

perception is reality. I've no doubt there are cases that upgrade in place doesnt work as well as fresh install, but I am skeptical that there is dramatic demonstrable differences between the two most of the time.

I believe it's likely more a benefit of clearing out the cruft that has accumulated over time rather than problems with the update itself. A lot of stuff gets installed over the years, and upgrading in place keeps the majority of that in place. Doing a fresh install and putting back only what you're currently using will probably result in fewer programs, daemons, drivers, etc that the system has to deal with.

For yosemite, I have a macbook pro that came with the OS and another macbook pro (nearly identical) upgraded from mavericks. No significant differences. I don't see why it should be like that this time and I would love to read a technical explanation.

Basically this. Yosemite was just such a very poor user experience.

Where do I download the petrol app?

I think that's an idiom.

It is! The Mac was just so very buggy and unstable with Yosemite.

arco.com , exxon.com , shell.com , chevron.com will give you local downloading locations.