d_gomaiste
Level 1 (0 points)

Q: Can't use Wi-Fi in El Capitan (or Yosemite)

Hey all —

 

For a few months now, I've been unable to connect to my home Wi-Fi network on my late-2012 iMac. It started out of nowhere with Yosemite 10.10.5 — everything had been running smoothly since I updated in late 2014, but suddenly stopped a few months ago. My Wi-Fi network will occasionally show up in the list of networks, but any time I try to join, I get the "cannot be joined" error. 

 

Today, I finally upgraded to El Capitan 10.11.3 and the problem persists.

 

All other devices in the house (a MacBook Air, a Windows laptop, and three iPhones) can connect without issue, so clearly this is a problem with my iMac. My phone and MacBook Air can both connect in the same room as my iMac, and the MacBook is still running 10.10.2. I've tried all of the usual suggestions:

 

- Deleting network prefs in Library/Preferences/SystemConfiguration, then rebooting

- Renewing DHCP lease

- Resetting PRAM

- Adding a new network location and using Google DNS

- Turning off Firewall

- Disabling AWDL

- Disabling Bluetooth

- Turning off Wi-Fi and Bluetooth on my iPhone 6 (iOS 9.3 beta)

 

I have the following peripherals: USB mouse, Bluetooth keyboard + Magic Trackpad, UAD Apollo Twin Solo, Native Instruments Maschine Mikro, and 2 external HDs.

 

I've had to resort to using my phone's hotspot to get work done, but now, it seems the Wi-Fi Hotspot and the Instant Hotspot no longer work and I have to use Bluetooth. Obviously, this is not viable long term.

 

A clean install would be a last ditch effort. The only Time Machine backup I have is one I made last night before updating to El Capitan. If it comes down to it, I wouldn't be opposed to backing up my /home folder, reverting to Mavericks, and reinstalling everything manually... I'd like to avoid this, of course.

 

Any advice or suggestions welcome. Thanks so much!!

iMac, OS X El Capitan (10.11.3)

Posted on Mar 18, 2016 3:20 PM

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d_gomaiste

Q: Can't use Wi-Fi in El Capitan (or Yosemite)

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  • Helpful answers

  • by ~Bee,

    ~Bee ~Bee Mar 18, 2016 3:43 PM in response to d_gomaiste
    Level 7 (31,787 points)
    Mac OS X
    Mar 18, 2016 3:43 PM in response to d_gomaiste

    d --

     

    Can you remember what changes you may have made just before "a few months now?"

    Please really look around your HD.  Anything changed or added around the time it stopped working.

    Did you add an "security" apps to your Mac?  Anything claiming to "clean your Mac?"

  • by d_gomaiste,

    d_gomaiste d_gomaiste Mar 18, 2016 4:34 PM in response to ~Bee
    Level 1 (0 points)
    Mar 18, 2016 4:34 PM in response to ~Bee

    Hi Bee, thanks for the reply!

     

    The only security app I have installed is Avast, which I've had for 3+ years and has never been an issue.

     

    Unfortunately, it's a little hard to figure out which software I installed around when the problem first arose. I'm constantly demoing new software and third-party plugins for my music/photo studio. These are usually trial apps that sometimes end up being deleted, but my install history is quite extensive, making it quite difficult to pinpoint the exact culprit.

     

    The only "major" change I made recently was this past November when I bought the UAD Apollo audio interface, which connects via Thunderbolt. Disconnecting this interface doesn't seem to change anything.

  • by ~Bee,

    ~Bee ~Bee Mar 18, 2016 5:12 PM in response to d_gomaiste
    Level 7 (31,787 points)
    Mac OS X
    Mar 18, 2016 5:12 PM in response to d_gomaiste

    Can you UNinstall Avast (according to the developer's instructions), restart your Mac, and test?

    It could very well be, if you've had it for 3 years, that it needs to be updated.  However, I would never recommend it.

    I know you've had it for three years, but many here have run into problems with it.  It's pretty well documented.

  • by Linc Davis,

    Linc Davis Linc Davis Mar 18, 2016 5:34 PM in response to d_gomaiste
    Level 10 (207,963 points)
    Applications
    Mar 18, 2016 5:34 PM in response to d_gomaiste

    1. If any USB 3 storage devices are connected, please disconnect them and test.

    2. If you have an AT&T "UVerse" modem/router, please change the network name and reset the network password.

  • by d_gomaiste,

    d_gomaiste d_gomaiste Mar 19, 2016 4:50 PM in response to Linc Davis
    Level 1 (0 points)
    Mar 19, 2016 4:50 PM in response to Linc Davis

    Hi Bee & Linc,

     

    Sorry for the delayed response —

     

    I tried uninstalling Avast, but to no avail. I also tried shutting down & removing all peripherals (except for the Bluetooth keyboard and Magic Trackpad), but still no luck. I also tried several other things:

     

    - Booting into Safe Mode (STILL could not connect to network)

    - Resetting the SMC

    - Restarting mDNSResponder (via Terminal)

    - Installing the latest software/firmware update for my UAD Apollo

     

    Unfortunately, the problem persists.

     

    Linc, my service provider WAS UVerse until a week ago when I switched to XFinity. I'm not sure if the UVerse router facilitated the issue...

     

    Anyway, I'm not sure what I else I could explore to solve this. I would love any further insight if possible. Thanks again for your help!!

  • by Linc Davis,

    Linc Davis Linc Davis Mar 19, 2016 5:12 PM in response to d_gomaiste
    Level 10 (207,963 points)
    Applications
    Mar 19, 2016 5:12 PM in response to d_gomaiste

    Please start up in Recovery mode. Can you connect to the network now?

  • by d_gomaiste,

    d_gomaiste d_gomaiste Mar 19, 2016 5:32 PM in response to Linc Davis
    Level 1 (0 points)
    Mar 19, 2016 5:32 PM in response to Linc Davis

    Sadly, no. I've also tried Online Recovery Mode and booting to the Startup Manager and it still can't be joined.

     

    Booting to Startup Manager, I get the same "can be joined" error. In Recovery Mode, it suggests I move closer to the router, and in Online Recovery Mode, it takes 10 minutes to recognize the network, and then simply rejects the password with no error message.

     

    EDIT: curiously, in Online Recovery Mode, it just joined the network, but only for a brief second, and is now back to refusing the login credentials.

  • by Linc Davis,

    Linc Davis Linc Davis Mar 19, 2016 5:37 PM in response to d_gomaiste
    Level 10 (207,963 points)
    Applications
    Mar 19, 2016 5:37 PM in response to d_gomaiste

    Make a "Genius" appointment at an Apple Store, or go to another authorized service provider. You may have to leave the machine there for several days.

    Back up all data on the internal drive(s) before you hand over your computer to anyone. There are ways to back up a computer that isn't fully functional—ask if you need guidance.

    If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.

    Keeping your confidential data secure during hardware repair

    Apple also recommends that you deauthorize a device in the iTunes Store before having it serviced.

    *An SSD doesn't need to be zeroed.

  • by d_gomaiste,

    d_gomaiste d_gomaiste Mar 19, 2016 6:00 PM in response to d_gomaiste
    Level 1 (0 points)
    Mar 19, 2016 6:00 PM in response to d_gomaiste

    Thanks for the suggestion, Linc. Unfortunately, I won't be able to take it to be serviced any time soon. I'm slammed with work for the next month and a half and really can't afford any downtime.

     

    Interestingly enough, I just tried moving my iMac within 10 feet of the router, and to my surprise, I was able to quickly connect to my home network without any dropouts. The connection, however, seems to be excruciatingly slow. I've read about this being an issue with Yosemite/El Capitan… would you happen to know of any solutions for this??

     

    If there's no sensible way to fix these issues, I'll probably just have to continue tethering (Instant Hotspot suddenly started working again) until I can either get it looked at or get frustrated enough to do a clean install and revert to Mavericks.

  • by Linc Davis,

    Linc Davis Linc Davis Mar 19, 2016 6:04 PM in response to d_gomaiste
    Level 10 (207,963 points)
    Applications
    Mar 19, 2016 6:04 PM in response to d_gomaiste

    Probably a disconnected antenna cable. The part is not user-serviceable.

  • by d_gomaiste,

    d_gomaiste d_gomaiste Mar 19, 2016 6:40 PM in response to Linc Davis
    Level 1 (0 points)
    Mar 19, 2016 6:40 PM in response to Linc Davis

    The only thing that makes me wonder if  might be something else is that my MacBook Air suddenly started displaying the same symptoms yesterday afternoon (after working perfectly for months).

     

    I haven't installed ANY new software on the MBA, and it sees considerably less use than my iMac. The ONLY new/unusual thing I did was attempt to share its Wi-Fi connection with my iMac via Thunderbolt. This was the first time I had ever plugged a Thunderbolt cable into my MBA. I'm now wondering if perhaps the Thunderbolt cable had something to do with the connection on both computers…

  • by Linc Davis,

    Linc Davis Linc Davis Mar 19, 2016 7:11 PM in response to d_gomaiste
    Level 10 (207,963 points)
    Applications
    Mar 19, 2016 7:11 PM in response to d_gomaiste

    Now the story has changed completely. If you're having the same problem with more than one device, the router is at fault, or you're dealing with interference.

     

    Potential sources of interference