Q: Wifi is incredibly slow on OS X El Capitan

Not only that Safari is sometimes tooo slow, it is quirky. If one tries to opens a website from 'Bookmarks', it may hang forever. To solve this,. I learned to go to the subject line, highlight the link, and hit Return. In many cases it will open faster. Why is that, beats me.

BTW, starting in 'Safe Mode' to solve one problem cost me another headache. After normal restart and when trying to open Office 2008 (yeah, it is still great and working), there was a problem first with a long delay and then with slow opening of the four elements. Days after, the Office opens after minute or two but not faster as before.

This is the only thing that solved my Wifi issues. Wifi would be connected but wouldn't even load a website. This fixed it and working perfectly now. I bought my MacBook Pro less than a week ago (Early-2015)

I have been having a similar issue since the upgrading to 10.11.3.  My wifi connected iMac would go through extreme slowness/no response across all browsers (Safari, Firefox and Chrome), mail also played up with errors (SSL) connecting to POP and IMAP accounts.  Some days it would be fine but most days it was rubbish.

Other devices (iPhone/iPad) connecting to the same router did not have any speed issues.

I have removed some redundant AV software, cleared browser caches, recreated the Wifi connection settings, and changed the DNS but nothing helped.  I also noticed that at the time the issue occurred there were SSL handshake error messages in the console log.

As another test I moved over to using ethernet and turned off the wifi, speed is back to normal and the SSL errors no longer show in console.

I am pretty keen to move back to the wifi however...

Does your router broadcast both a 2.4Ghz and a 5Ghz wifi network at the same time? If so it might be worth logging in to your router admin page and turning off one or other of those two networks. It worked for me (turning off the 5Ghz one in my case) and a few others on this thread ...

Appears to be only broadcasting at 2.4Ghz, it is a Billion 7800N.

One thing for sure. The moment I turned off Google Drive using Activity Monitor, the Safari response got better. The pages are opening faster.

Google drive is off.  It is still unusable/complete rubbish.

Well, the update 10.11.4 will be here probably by mid March. Let's hope this will be fixed.

I believe that the major issue is 3rd party software incompatibility with 10.11.3. I have deleted almost every app that I have except for MS office and then went through and ensured that everything else was upgraded to the latest version. After running Etrecheck at least 15 times, there is no more red. Additionally, I have removed plists and other things from areas (i.e. the directory utility in Users and Groups) that I frankly wasn't sure I should and finally my macair is back running the way it did before the upgrade. I am even able to use my wireless mouse although I do only have this machine only accessing my wireless n/w on 2.4ghz. There are 4 other apple devices in the house and they have no problem switching between 2.4 and 5 ghz.  kernel_task is still the largest consumer of CPU,memory and disk but I no longer get any beachballing. 

Fingers crossed .... meanwhile it's a FARCE

@sdf007 thanks for your input.

My case is simple: except MS Office 2008, I have no extra software or at least nothing that I haven't upgraded from Lion.

I have no added extentions or gaming software.

So, I still think this is a OS X 10.11 problem. MacBookPro was not so slow while I was using Snow Leopard and Lion.

Bob I would check the revision level of everything you have. I was in the same position as you. Run etrecheck continually until you eliminate all the red items. I really can't help you on specific trouble shooting as it was a continual process with me, sometimes I spent 2 hours a day for the better part of two weeks until I understood what some of the "volunteers" were actually saying about deleting plists and other files. I set up a second clean admin account that had no documents and downloaded my important data to a thumb drive. It really is very frustrating as I had a perfectly functioning macair before the upgrade. If I did not mention it before I did get rid of adobe flash, this did not solve the problem, but I haven't experienced an issue with not having it either. If someone could ever develop an automated software compatability app, that would be a winner.................good luck

sdf007 wrote:

 

Run etrecheck continually until you eliminate all the red items.

Hello sdf007,

While I'm all for EtreCheck, obviously, I have to caution you about the red items. I only use red to get attention. It doesn't necessarily mean there is anything wrong. It depends on the circumstances. I know that is confusing and I wish I had a better answer than that. But an automated tool like EtreCheck really can't distinguish between a "normal failure" and a failure that needs to be investigated. Plus, I simply don't have that many different colours and styles with which to convey information.

@jubamad - this is the one... thank you!

Well, probably with more luck than brains, the approach I described worked without having to wipe my disk and do a completely clean install. So, I understand you have to say what you said, but through a very tedious process, using your tool, I was able to fix my problem with no issues since about March 3rd. I hope I never have to do that again.