Johan-

Q: Cannot switch wi-fi on

I can use wi-fi flawlessly for a couple of hours. Then suddenly it seems like the connection is lost: loading any new webpage won't happen. Then I switch off wi-fi from the menu bar, with the intention to switch it back on. Strangely the latter is impossible: Switching on wi-fi neither works from the menu bar, nor from the network preference pane. Nothing seems to happen when I click it. The same holds for the corresponding terminal command "networksetup -setairportpower en1 on". The only way I have found to 'fix' it is a restart, but a few hours later it happens again. I think this all started after a sudden reboot a few days ago, of which I have no idea of the cause either.

 

I've already tried some general wi-fi issue remedies I stumbled upon, but to no avail:

  • Making wi-fi inactive and then active again
  • Removing wi-fi from the preference pane and re-add it
  • Adding a new location
  • Removing the contents of /Library/Preferences/SystemConfiguration/
  • Resetting NVRAM
  • Resetting SMC

 

I have a mid 2012 13-inch MBP with OS X Yosemite 10.10.5 and all updates installed. Any suggestion of what I could still try is welcome.

MacBook Pro, OS X Yosemite (10.10.5), null

Posted on Oct 14, 2015 11:58 AM

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Q: Cannot switch wi-fi on

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  • by Johan-,

    Johan- Johan- Oct 14, 2015 1:23 PM in response to Johan-
    Level 1 (0 points)
    Oct 14, 2015 1:23 PM in response to Johan-

    Addition:

     

    I've also already tried solving it by repairing permissions.

    Going into sleep mode and back also 'fixes' wi-fi for a while

  • by Linc Davis,Helpful

    Linc Davis Linc Davis Oct 15, 2015 5:11 AM in response to Johan-
    Level 10 (208,000 points)
    Applications
    Oct 15, 2015 5:11 AM in response to Johan-

    1. This procedure is a diagnostic test. It changes nothing, for better or worse, and therefore will not, in itself, solve the problem. But with the aid of the test results, the solution may take a few minutes, instead of hours or days.

    The test works on OS X 10.7 ("Lion") and later. I don't recommend running it on older versions of OS X. It will do no harm, but it won't do much good either.

    Don't be put off by the complexity of these instructions. The process is much less complicated than the description. You do harder tasks with the computer all the time.

    2. If you don't already have a current backup, back up all data before doing anything else. The backup is necessary on general principle, not because of anything in the test procedure. Backup is always a must, and when you're having any kind of trouble with the computer, you may be at higher than usual risk of losing data, whether you follow these instructions or not.

    There are ways to back up a computer that isn't fully functional. Ask if you need guidance.

    3. Below are instructions to run a UNIX shell script, a type of program. As I wrote above, it changes nothing. It doesn't send or receive any data on the network. All it does is to generate a human-readable report on the state of the computer. That report goes nowhere unless you choose to share it. If you prefer, you can act on it yourself without disclosing the contents to me or anyone else.

    You should be wondering whether you can believe me, and whether it's safe to run a program at the behest of a stranger. In general, no, it's not safe and I don't encourage it.

    In this case, however, there are ways for you to decide whether the program is safe without having to trust me. First, you can read it. Unlike an application that you download and click to run, it's transparent, so anyone with the requisite skill can verify what it does.

    You may not be able to understand the script yourself. But variations of it have been posted on this website thousands of times over a period of years. The site is hosted by Apple, which does not allow it to be used to distribute harmful software. Any one of the millions of registered users could have read the script and raised the alarm if it was harmful. Then I would not be here now and you would not be reading this message. See, for example, this discussion.

    Another indication that the test is safe can be found in this thread, and this one, for example, where the comment in which I suggested it was recommended by one of the Apple Community Specialists, as explained here.

    Nevertheless, if you can't satisfy yourself that these instructions are safe, don't follow them. Ask for other options.

    4. Here's a general summary of what you need to do, if you choose to proceed:

    ☞ Copy a particular line of text to the Clipboard.

    ☞ Paste into the window of another application.

    ☞ Wait for the test to run. It usually takes a few minutes.

    ☞ Paste the results, which will have been copied automatically, back into a reply on this page.

    These are not specific instructions; just an overview. The details are in parts 7 and 8 of this comment. The sequence is: copy, paste, wait, paste again. You don't need to copy a second time.

    5. Try to test under conditions that reproduce the problem, as far as possible. For example, if the computer is intermittently slow, run the test during a slowdown.

    You may have started up in safe mode. If the system is now in safe mode and works well enough in normal mode to run the test, restart as usual before running it. If you can only test in safe mode, do that.

    6. If you have more than one user, and only one user is affected by the problem,, and the affected user is not an administrator, then please run the test twice: once while logged in as the affected user, and once as an administrator. The results may be different. The user that is created automatically on a new computer when you start it for the first time is an administrator. If you can't log in as an administrator, test as the affected user. Most personal Macs have only one user, and in that case this section doesn’t apply. Don't log in as root.

    7. Load this linked web page (on the website "Pastebin.") The title of the page is "Diagnostic Test." Below the title is a text box headed by three small icons. The one on the right represents a clipboard. Click that icon to select the text, then copy it to the Clipboard on your computer by pressing the key combination command-C.

    If the text doesn't highlight when you click the icon, select it by triple-clicking anywhere inside the box. Don't select the whole page, just the text in the box.

    8. Launch the built-in Terminal application in any of the following ways:

    ☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

    ☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

    ☞ Open LaunchPad and start typing the name.

    Click anywhere in the Terminal window to activate it. Paste from the Clipboard into the window by pressing command-V, then press return. The text you pasted should vanish immediately.

    9. If you see an error message in the Terminal window such as "Syntax error" or "Event not found," enter

    exec bash

    and press return. Then paste the script again.

    10. If you're logged in as an administrator, you'll be prompted for your login password. Nothing will be displayed when you type it. You will not see the usual dots in place of typed characters. Make sure caps lock is off. Type carefully and then press return. You may get a one-time warning to be careful. If you make three failed attempts to enter the password, the test will run anyway, but it will produce less information. If you don't know the password, or if you prefer not to enter it, just press return three times at the password prompt. Again, the script will still run.

    If the test is taking much longer than usual to run because the computer is very slow, you might be prompted for your password a second time. The authorization that you grant by entering it expires automatically after five minutes.

    If you're not logged in as an administrator, you won't be prompted for a password. The test will still run. It just won't do anything that requires administrator privileges.

    11. The test may take a few minutes to run, depending on how many files you have and the speed of the computer. A computer that's abnormally slow may take longer to run the test. While it's running, a series of lines will appear in the Terminal window like this:

    [Process started]
            Part 1 of 8 done at … sec
            …
            Part 8 of 8 done at … sec
            The test results are on the Clipboard.
            Please close this window.
    [Process completed]

    The intervals between parts won't be exactly equal, but they give a rough indication of progress. The total number of parts may be different from what's shown here.

    Wait for the final message "Process completed" to appear. If you don't see it within about ten minutes, the test probably won't complete in a reasonable time. In that case, press the key combination control-C or command-period to stop it. Then go to the next step. You'll have incomplete results, but still something. If you close the Terminal window while the test is still running, the partial results won't be saved and you'll have to start over.

    12. When the test is complete, or if you stopped it because it was taking too long, quit Terminal. The results will have been saved to the Clipboard automatically. They are not shown in the Terminal window. Please don't copy anything from there. All you have to do is start a reply to this comment and then paste by pressing command-V again.

    At the top of the results, there will be a line that begins with the words "Start time." If you don't see that, but instead see a mass of gibberish, you didn't wait for the "Process completed" message to appear in the Terminal window. Please wait for it and try again.

    If any private information, such as your name or email address, appears in the results, anonymize it before posting. Usually that won't be necessary.

    13. When you post the results, you might see an error message on the web page: "You have included content in your post that is not permitted," or "The message contains invalid characters." That's a bug in the software that runs this website. Please post the test results on Pastebin, then post a link here to the page you created.

    14. This is a public forum, and others may give you advice based on the results of the test. They speak for themselves, not for me. The test itself is harmless, but whatever else you're told to do may not be. For others who choose to run it, I don't recommend that you post the test results on this website unless I asked you to.

    ______________________________________________________________

    Copyright © 2014, 2015 by Linc Davis. As the sole author of this work (including the referenced "Diagnostic Test"), I reserve all rights to it except as provided in the Use Agreement for the Apple Support Communities website ("ASC"). Readers of ASC may copy it for their own personal use. Neither the whole nor any part may be redistributed.

  • by Johan-,

    Johan- Johan- Oct 15, 2015 5:11 AM in response to Linc Davis
    Level 1 (0 points)
    Oct 15, 2015 5:11 AM in response to Linc Davis

    Thank you. The results from your script helped me getting to a conclusion I should have drawn earlier: After migrating ever since Tiger, a clean OS X install might not be a bad idea.

  • by Linc Davis,

    Linc Davis Linc Davis Oct 15, 2015 9:00 AM in response to Johan-
    Level 10 (208,000 points)
    Applications
    Oct 15, 2015 9:00 AM in response to Johan-

    Back up all data to at least two different storage devices, if you haven't already done so. One backup is not enough to be safe. The backups can be made with Time Machine or with Disk Utility. Preferably both.

    Erase and install OS X. This operation will destroy all data on the startup volume, so you had be better be sure of the backups. If you upgraded from an older version of OS X, you'll need the Apple ID and password that you used, so make a note of those before you begin.

    When you restart, you'll be prompted to go through the initial setup process. That’s when you transfer the data from a backup.

    Select only users and Computer & Network Settings in the Setup Assistant dialog—not Applications or Other files and folders. Don't transfer the Guest account, if it was enabled.

    If the problem is resolved after the clean installation, reinstall third-party software selectively. I can only suggest general guidelines. Self-contained applications that install into the Applications folder by drag-and-drop or download from the App Store are usually safe. Anything that comes packaged as an installer or that prompts for an administrator password is suspect, and you must test thoroughly after reinstalling each such item to make sure you haven't restored the problem. I strongly recommend that you never reinstall commercial "security" products or "utilities," nor any software that changes the user interface or the behavior of built-in applications such as Safari. If you do that, the problem is likely to recur.

    Before installing any software, ask yourself the question: "Am I sure I know how to uninstall this without having to wipe the volume again?" If the answer is "no," stop.

    Never install any third-party software unless you know how to uninstall it.

  • by Johan-,

    Johan- Johan- Oct 15, 2015 9:48 AM in response to Linc Davis
    Level 1 (0 points)
    Oct 15, 2015 9:48 AM in response to Linc Davis

    The symptoms showed up again and I've been running the script again. The kernel log message that, judging from the time stamp, seems to be related to this issue is:

     

    ARPT: *****.******: wl0: _wlc_ioctl: dead chip, off[0] [0xffffffff]

     

    With this information I finally found another thread with people reporting this issue. The bad news is that even a clean OS X install is reported not to solve this issue. I'll try that anyway, but that will have to wait until next week.

     

    Thank you for the third-party software advice, but I'm afraid that in this less-then-perfect world I'm never sure that any software can be removed without leaving a trace.

  • by Johan-,

    Johan- Johan- Oct 24, 2015 5:01 PM in response to Linc Davis
    Level 1 (0 points)
    Oct 24, 2015 5:01 PM in response to Linc Davis

    Update: I just installed El Capitan without migrating anything. Things went from bad to worse. Wi-fi hasn't worked at all since the first time the clean OS was booted. The task bar icon was blinking quite fast between the 'wi-fi off' symbol and 'searching'. I've uploaded the test report of your script here.

  • by Johan-,Solvedanswer

    Johan- Johan- Nov 13, 2015 2:03 PM in response to Johan-
    Level 1 (0 points)
    Nov 13, 2015 2:03 PM in response to Johan-

    The problem appeared to be hardware: a malfunctioning cable. Having it repaired at an Apple store is remarkably cheap. Case closed.