El Capitan running slowly?

Something is really hogging memory and/or the processor. I would try ejecting and disconnecting external drives (all of them) and restarting your computer and see if that helps. If performance returns to normal, run utilities on all of your drives, starting with the internal drive. Repair any corruption. Be sure to test the Time Machine backup drive. If it has problems the Mac will use every bit of memory and processing power to attempt the backup and you will be virtually unable to use the machine.

There are a lot of possible causes for what you are experiencing but give this a whirl.

Exactly same conclusion as JasonHaven - mail seems to have a bug...

Late 2011 MBP here. Initially El Capitan was running smoothly, but suddenly everything froze, and it became extremely unresponsive. Restarted several times, launched in safemode, even did a reinstall of the system. But every time the machine would suddenly just freeze up, and become slow.

But I realised it had something to do with Mail, and that everything works fine as long as mail is not running! I have tried to disable both my e-mail accounts, but even with no active mail accounts, launching Mail will make my computer extremely slow.

Any suggestions to resolve this? Or do I simply hope an update from Apple will fix this?

It's absolutely awful - so sloooow, I almost can't believe this is true in the year 2015. :-(((( It started with the installation process that took me about four hours. Then my MacBook already stalled and showed the beachball after entering the initial password - I had to reboot in "safe mode" until I finally glimpsed the standard background of my desktop.

Now most of the time I just endlessly watch the beachball. Microsoft Office apps such as Excel, Word or PowerPoint NEVER even come near a start - the icons in the dock just bounce up and down until I have to force quit the programs. And I don't have any kind of special third-party programs that might be to blame - just a standard MacBook with plenty of empty disk space.

This is a devastating experience - my computer has become useless!! Until somebody comes up with a really simple and helpful solution, I can only recommend to stick with whatever previous Mac OS you are running - everything older must definitely be better and faster than this Capitan stuff. And I have been using and recommending Macs for 27 years...

I never install a new system without first inspecting and prepping the drive, repairing any problems and optimizing it. (Disk Warrior works great for this) If there is corruption and a system is installed it can spell all sorts of performance trouble after the installation. Also important to check is how much free space is on the drive. If the drive is getting full, upgrading the OS can kill performance because there simply isn't enough free space. A very full drive can both make he Mac VERY slow and make it quite unstable. Check the amount of free space you have and, if you have less than 20% or the drive's capacity, remove large files (like videos) until the drive has plenty of free space again.

You may be on to something here. When El Capitan first started up, it brought up the Mail App and I don't ever use this app. So it may very well have something to do with that.

Try this , I did and it helped speed it up :

1. Shut down your Macbook
2. Plug it into the power socket
3. Hold down the left shift, option and control keys together with the power button for 10 seconds (your Macbook shouldn’t turn on)
4. Turn on your Macbook like normal.

UPDATE: I now notice El Capitan is running faster. I think the poster who commented about the Spotlight indexing may have been right (at least in my case.) I do think there is an issue with Mail still and I know I've had some issues with the Mail program with past OS versions as well. I used Disk Warrior and since there isn't a version of Onyx for El Capitan yet, I used a version of Clean My Mac to free up some space. I'm hoping after some additional bug fixes things will smooth out.

Normally I wait awhile before updating to new systems to allow time for bugs to be worked out. My wife and I are getting new iPhones soon and I think I was an eager beaver to get my laptop up and running with the latest OS in preparation!

Indeed, same thing happened to me as well, right after my Macbook booted up, after installing the update, I was greeted with the Mail app, bouncing in my dock, although the app isn't pinned in dock even, and I don't normally use it. So, I went ahead with it, set it to my Gmail account, but alas, it crashes after I open a few messages, invariably.

Also, the thing that's bothering me the most so far, is when I open System Preferences, I got it bouncing on my dock like never before, it takes a few good seconds to open, compared to Yosemite.

removing old extensions, little snitch & Sophos Av & a PR reset (hold control option P & R at start) sped up the iMac 2013 we have. during the slowness it took over an hour to copy a 25 MB file from one folder to another. Now its fine, normal speed resumed.

My Late 2008 MacBook with 8GB Ram and 256GB SSD is actually working faster than Yosemite with no slow downs.

Incredible - thanks a lot, you've made my day! Now almost everything is working as usual again, only the Microsoft Office stuff (what else...?) is still just bouncing.

I wish I had the same luck you did. It's not Mail for me—I can shut it down and it makes no difference. It certainly is related to printers. All my printers were removed post-installation, and when I try to add them back, the spinning ball never stops. I left the computer on overnight to allow Spotlight indexing to finish (someone else's suggestion) and things were moving faster in the morning. But after I restarted, everything reverted to the glacial pace I experienced yesterday.

Screen shot of Activity Monitor with Mail running. (Look at Mail's usage over 10GB!). Note Memory Pressure.

Screen shot of Activity Monitor with Mail QUIT running. Note Memory Pressure starts returning to normal.

I am having a similar problem here on my 2012 macbook pro. I recently updated to Yosemite from mavericks, everything was fine. It was quick and responsive. but a couple of days later I updated from yosemite to el capitan just when it was released. And I'm now having some annoying lag, unresponsiveness and slow app launching!. isn't el capitan supposed to have better performance and speed than yosemite???!!! Definitely weird.

For me, Mail is showing only 83.4MB, so Mail isn't the problem.

I don't know yet if Spotlight is the problem..but man..I do regret upgrading!!!!

Ugly new spinning wheel that is not even centered popping up EVERY FRIGGIN TIME!!!!

Why couldn't they setup spotlight to update at like 2am or something as a default????