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I cannot find the file

removing the network interfaces.plist does the trick!!!

When i deleted NetworkInterfaces.plist my wifi becomes inactive and wont switch on when i hit "Apply" button. I returned NetworkInterfaces.plist and then deleted NetworkInterfaces.plist and Preferences.plist together and restart. After that everything worked like a charm. Backup yours before doing same trick. Goodluck!

Martin, it really work´s!

Thank you very much!!

MBP Mid 2010:

Had to replace the motherboard. The tech forgot to enter the serial number for the new board. This was why I couldn't use iMessage or FaceTime. Went to Apple and got the S/N entered. Problem Solved.

Sorry if this doesn't help.

GO TO>> Apple Menu>> About this Mac >> More info: S/N is supposed to be found there. If not, that's your problem

thanks! that did the trick!

Thank you brianfromboro! You have resolved an issue I have been dealing with for 3 months. This fixed the issue of the -50 error, my 5002 error, and also fixed my cabled intranet "cable not connected" error. You are a blessing and a genius! Have you applied for a tech job at Apple? They need you, imho.

Here's the fix that works for the majority.

1. Reset Safari

2. Restart Mac

3. Sign in to App Store

Works!

just deleting /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist didn't work for me.

I read that your ethernet device name needs to be en0 and mine was en2

to see the device name goto apple logo > about this mac > system report > network

you will see a list of your network interfaces, check if ethernet is at en0 (under column BSD Device Name)

mine was at en2 so I went into system preferences > network and clicked the minus to delete interfaces and then deleted /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist

rebooted and went back to system preferences > network and added the ethernet back (click plus and add) the wifi was already there for me at en1 so I didn't need to add that.

then checked the system report and ethernet was at en0

went to the app store and BAM! it finally worked 🙂 😀

after 8 hours with a tech in apple chat one day, and 2 hours on the phone the next day, here are the steps we took to solve my problem:

Here is an FYI for anyone interested in the trouble I went through and how we finally resolved it. You mileage may vary.

What had happened, and it probably wasn’t the fault of El Capitan, was a plist file got corrupted be they had no idea how it could corrupt that same file even in a time machine backup that was working fine back then. Here are the steps we used to solve it.

1. open “finder”, click on the computer internal hard drive.

2. click on Library

3. click on preferences

4. click on systemconfiguration folder

5. inside that folder find networkinterface.plist file and drag it to trash.

Restart computer. The plist will remake itself. open app store and try to log in (be hooked up with a cable to your router). Ok that sounds simple enough, but after 8 hours in apple chat they were unable to get my computer to reconnect to my wifi (my ethernet card is dead so I can only use wifi). We finally had to delete the new plist and drag the old one back in to get hooked up to my wifi router, and of course the problem was still there. So, when I was talking to apple tech today (for 2 hours), they had me do the same thing (I told them it wouldn’t work because we couldn’t get wifi), but the new tech knew what he was doing and he took me a step further. After restarting the computer we went to step 2.

1. open system preferences in your applications folder

2. click on network

3. on the left side of network window is a list of of connections. we turned off wifi and deleted my wifi connection.

4. then click on the “+” at the bottom of list on the left and add a wifi connection (pick your router from the list)

5. click on advanced in the bottom right of the window and in the TCP/IP tab, make sure the first line “configure IPv4” line shows “using DHCP”. If it doesn’t, click on the arrows on the right and choose that

6. then click on the “renew DHCP Lease”

7. click OK

8. click “apply” in the main window.

The wifi connected and everything worked. Even though it probably wasn’t the fault of El Capitan (but it could have been), I wish the 8 hours I spent on chat with apple support could have taken me to step 2 and got it working so I wouldn’t have had to spend 2 days re-installing and restoring various OS X systems, and I would still be on el Capitan. However, I’ve gone back to Yosemite as my last resort (and it still didn’t work) so I’m going to stay on Yosemite with this computer.

This worked perfectly for me. Thanks!

1> Go to itunes as per usual, on the menu bar click store.

2> Click 'Authorize This Computer..'

I know its too late but it can be useful in future 😀

I tried that. It didn't work for me. But my instructions above did work.

Saw this error today for the first time while trying to launch an app purchased from the Mac App Store. Deleting "Macintosh HD/Library/Preferences/SystemConfiguration/NetworkInterfaces.plist" and rebooting seems to be the fix as suggested in this thread. Possible Norton Security was blocking it from working but I havent seen any evidence of that so far.

I also saw this error for the first time today. Unfortunately, deleting "Macintosh HD/Library/Preferences/SystemConfiguration/NetworkInterfaces.plist" and rebooting has not worked.