Unable to Enable WiFi under El Capitan except in Safe Mode

Hello,

I thought I would stop by to update this thread since so many topics like it end without the OP indicating what finally resolved the problem. To first answer your question, at one point I tried to download EtreCheck but it would not run on El Capitan where the problems had occurred. (Couldn't find a version old enough on the EtreCheck website that would run.)

All I can report is that WiFiProxy repeated frequently in the log and that Wireless Diagnostics was not able to power on the interface (nor could I do it through Terminal) so in the end I ran out of ideas. If I had to guess, I think it may have been an owners/groups/permissions issue because the only major issue I ever had to date on this iMac related to some permissions I royally screwed up between the two macOS partitions.

I had an old copy of TechTool Pro on the Snow Leopard partition that reported a lot of High-Fly Write errors on my disk, an Apple Hardware Test that reported an HD fan issue but other than that AHT, TechTool and DiskUtility insisted that the disk was otherwise good (same for the memory).

Due to the hard drive fan and the longstanding WiFi issue it had been my plan for awhile to replace the HD and WiFi card (which I already had on hand) so I even did that and STILL the problem persisted. (Although it should be noted that I cloned El Capitan so whatever problems it had came with the new install.)

In the end, I gave up and upgraded El Capitan to High Sierra. The good news? WiFi immediately began working. Bad news? I ended up with a black screen after the update. No sooner did I enter my login at startup and the screen would go black. No amount of SMU/PRAM resets resolved it.

The only thing visible to me in that state were the notifications. Thankfully one came up asking me if I wanted to learn more about High Sierra. I clicked that and it launched Safari. From Safari I was able to get to Spotlight and from Spotlight to make use of Terminal. After repairing permissions and dumping caches in Terminal, I noticed that my desktop image had returned (no longer a black screen behind the window). From there I was able to select High Sierra in System Preferences and make it the preferred startup disk. Only then was I successful booting into Safe Mode (prior to this all efforts to get into Safe Mode resulted in Safe Mode for the default startup volume, not the High Sierra partition). After two restarts in Safe Mode, it came back up without prompting me to login.

I now see a black screen briefly appear before the desktop loads and then everything is normal. Well, I should clarify "normal". Everything seemed to work fine until I tried to launch iTunes and the App Store. I'm logged in with my iCloud under System Preferences but the App Store has an old email in it that is no longer present on my other App Store/devices.

Several months ago I logged into my Apple ID and updated my email, so the presence of this old email in the App Store wasn't caused by creating a second Apple ID. (App Store had been accessible under El Capitan before the upgrade.) When I try to launch iTunes and go to Accounts to login, it eventually crashes without doing anything. When I go to the App Store and attempt to sign out of the old email, nothing happens. I have left it as long as an hour and it doesn't time out, either. So currently I am stuck in a troubleshooting loop, this time with High Sierra vs. El Capitan. But hey, at least the WiFi works!

For software troubleshooting, my list of third-party extensions when viewed through About this Mac>System Profile is surprisingly short (only two I don't recognize). For startup items, I first disabled Amazon Music (later deleted it with TrashMe). Also stopped Evernote from launching at startup. Still have Weatherbug, an App Store purchase called Monty and a utility called f.lux (dims screen and neutralizes the blue light from the display after sunset). The last item I still have in operation is a utility called SMCfancontrol (HD doesn't report any errors using DiskUtility but I installed it as a precaution due to an Apple Hardware Test HD fan error first reported a couple years back). The oldest third-party app I have installed is called TotalFinder (don't recall why I originally downloaded it, only that it was a royal pain to install).

Cocktail saved my bacon when I was having the system-wide permissions problems a few years ago so I would hate to ditch it. (Also helps to speed up my Mac when I run it periodically.) However, I notice it's not in the App Store (I take it that's a negative). Meanwhile, I have a MacBook Pro on the same macOS and no issue. (The MacBook Pro also has an old copy of McAfee TP installed but I'm too afraid to remove it without the benefit of a McAfee uninstaller and risk an otherwise working system.)

What doesn't make sense is that all of the aforementioned software was present long before the WiFi problems started and most of it (exception being SMCfancontrol) is also running on the MBP without issue.

As mentioned, when I hit "apply" for changes made to the WiFi interface they don't take. Could it be a permissions issue of some sort? I know how to do a "Get Info" and view the Permissions that are present — but how many files/locations would I have to Get Info on to determine whether or not the macOS has proper access to make changes to the WiFi interface?

If I have to delete Weatherbug, SMCfancontrol, TotalFinder, Evernote, Monty, Cocktail and f.lux I will — but I just wish it would be easier to determine which third-party app is the issue (if any) before I throw every last one of them away.

"You mention in your post, that your iMac cannot gain access to the the Internet via Wi-Fi, but can it gain access to the local wireless network? That is, can it "see" other devices on the local network and communicate with them?"

That's a good question. It looks like it "sees" things (listed as shared/available devices) but when I go to connect it fails. I have to use Ethernet or reboot into another partition where WiFi continues to work for a successful connection to occur.

The only thing I haven't really dug into is the router. (The router is set to update itself automatically so maybe it was some kind of update that went through?)

I also wasn't aware that Safe Mode makes repairs. But now that you mention it, after I reinstalled OS X it randomly began rebooting into Safe Mode instead of my preferred partition (first time I have ever had this happen). On about three of those occasions, I saw some white text in the upper left corner against a black background having to do with a kernel panic. (It scrolled by too fast to understand which process was involved.) However, when I ran Disk Utility from Recovery I didn't get errors there. (I even ran Disk Utility out of the older operating system where it is still possible to repair permissions and nothing came up that I haven't seen before.) Eventually it stopped booting in Safe Mode but I went ahead and reinstalled 10.11.6 a second time just in case something was messed up (haven't seen it boot into Safe Mode since). Unfortunately, still no WiFi…