Is El Capitan that unstable??

So far I have not experienced any problems with El Capitan on either of my Macs.

I have El Capitan running on a mid-2010 MacBook, and I've had no troubles whatsoever. Just what exactly are you using to "clean up" your hard drive? If it's any of the following programs (not to mention others I didn't name), I would immediately stop and uninstall it following the developer's instructions:

• AVG Cleaner
• CCleaner
• CleanMyMac
• MacCleaner
• MacKeeper
• Memory Cleaner
• TuneMyMac

People experience slowness/lagginess/freezing/dragging for more than a few reasons. Their hard drive could be failing, the hard drive could be too full, they could have a bunch of incompatible apps/plugins/extensions/drivers that don't work with El Capitan, they could have installed anti-virus/maintenance programs (like the ones listed above), they could need to add more RAM....the list goes on. 90% of the time, people's issues with El Capitan are cleared up by dealing with one of the problems just listed. For a small group of people, it's something other than that. If you're going to upgrade your system, make sure you take the following steps first:

1. Check that all of your currently installed apps/plugins/extensions/drivers are compatible with El Capitan. If they're not, update them so they are. If they can't be updated, uninstall them. If you can't uninstall them because they're essential to employment, then don't upgrade your OS.
2. If you've taken care of #1, make a full backup of your system using either Time Machine or a program like CarbonCopyCloner. In the rare instance something goes wrong, or if you just plain decide you don't like El Capitan, you can use that backup to restore system to before the upgrade.
3. If you have any of those aforementioned "maintenance" programs on your computer, or if you have any anti-virus programs on your computer, uninstall them completely following the developer's instructions. You can find them on the developer's website.
4. When you download the installer from the App Store, stop the process before it can be installed. Move a copy of the installer to another folder, because while it downloads to your Applications folder, once the installation starts, it goes away. It's always good to have a backup of the installer in case something happens and you need it.

I've put it on a 2012 Mini and a 2010 MBP (core 2 duo) and it runs fine.

I don't dump all over it with crapware, so it pretty much upgrades without issue all the time.

I don't know what versions of Photoshop will work, but Office 2011 does as long as you keep it updated.

El Capitan 10.11.4 is on my 2011 Mac mini (16GB) with SSD, the 2009 Mac mini(4GB), and a 2014 MacBook Air(4GB). It functions perfectly on all three of my machines.

Most of the negative emphatic posts that you see about El Capitan problems in the support community are from people that have incompatible third-party software issues, have infected their machine with malware (not viruses) from web surfacing, and/or email phishing, or running absolutely useless anti-virus, or so-called cleaner applications. And there are a few Darwin award contenders that remove parts of their operating system to free up space or simply get rid of what they don't want or need — and then the OS bites back.

There are a gazillion different Macs around, and somebody is always having a problem with something or another. El Capitan is seemingly a complete and absolute disaster if you're fond of filling your Mac with dreck, malware and junk, or if you prefer to modify parts of the operating system directly and don't want to turn off the system integrity protections intended to block those changes in El Capitan, and there's always a good chance for "fun" with add-on anti-malware and add-on anti-virus and such. But then the same sorts of problems can and have arose on earlier OS X releases, too. There are also cases were some of the older printers and some older software has fallen off of support within an OS X release, too. But if you're running without add-ons and such, then make a backup or two to external storage, upgrade, and have a look around. That test upgrade is the only way you'll really know for sure, after all.

Hi Atcandela:

I have an MacBook Pro 13 inch early 2011 and am running El Capitan 10.11.4 with no problems.

You have not indicated how much memory you have.

El Capitan runs best on at least 8GB of RAM.

You can check at RoaringApps.com for any software which may be incompatible with El Capitan.

Kim

If El Capitan were "unstable" no one would use it, or should.

Read Upgrade to OS X El Capitan - Apple Support.

Assuming that you are already in the habit of routinely backing up your system you can evaluate El Capitan at no risk and at no cost. If you do not routinely back up your system, you should. Obtain an external USB, FireWire, or Thunderbolt hard disk drive for your Mac, then download and install El Capitan on it. You can choose to start your Mac from that disk or the internal one using Startup Manager (hold an option key while you start your Mac), and evaluate El Capitan at no risk whatsoever to your existing installation. Just be sure to designate the proper installation location for El Capitan when you get to that installation step.

Running OS X from an external USB hard disk won't be as fast as the Mac's internal one, but it will be sufficient to draw conclusions regarding its suitability for your needs.

An external hard disk drive of adequate capacity can be purchased for well under $100 - much less than the cost of some previous OS X upgrades themselves. When you satisfy yourself that El Capitan works for you, then "clone" the external disk's contents to your internal one, and use the external disk for backup purposes — which you ought to be doing anyway.

You could clone your system to an external drive and then upgrade the clone. If your older apps are working with Yosemite, they may work OK with El Capitan. Nothing compels you to burn your bridges and upgrade without a safety net (complete backup, keep previous system, etc.).

I'm not using El Capitan for anything serious, but it seems pretty snappy in my limited use of it. You didn't mention how much RAM you have installed — 8 or 16 GB would be advisable. You may also find El Capitan somewhat slow if your internal hard drive is the stock 5400 rpm drive that came with the MBP.

Atcandela wrote:

That's the right idea. Creating a back up (Time Machine) then do the upgrade.

But if the upgrade isn't to your liking then you're out of luck downgrading back to Yosemite.

That's not - quite - right. Time Machine conveys the ability to revert to any previous system state, including its operating system, given the number of available backups it contains, which is ultimately limited by the capacity of the backup device.

You can conceivably have years upon years of available backups and operating systems from which to choose. If yesterday's Time Machine backup contains a backup of your Yosemite system and you want to revert to it, it's as simple to do that as it would be to revert to a Lion installation from five years ago, as long as that backup remains.

Atcandela wrote:

Though I believe it doesn't revert back to OS Yosemite, correct?

Would I have to do clean install to go back to Yosemite?

No. It's just like I wrote: using Time Machine you can revert to any previously backed up system. If you were to do that, you would be following the instructions in the following Apple Support document: Use Time Machine to back up or restore your Mac - Apple Support. The instructions under "Restore Everything" explains how to recover an entire system, including its operating system.

It would be a good idea to disconnect the backup drive, or temporarily turn off Time Machine while evaluating El Cap. Otherwise, the possibility exists that a subsequent backup might erase a previous backup. Time Machine will retain as many older backups as possible given the capacity of the backup device, but if it only has the capacity for one complete system, that is all it is guaranteed to retain. It is not designed or intended to archive countless numbers of earlier systems.

I'll "test drive" El Capitan" from my external HD and see how it runs.

That's another way to do it. It is preferable because all you would need to do to revert to your previous installation would be to simply restart your Mac normally — in other words, without using Startup Manager to boot from the external hard disk drive.