Your device or computer could not be verified. Contact support for assistance.

None of this worked for me. I went to a TimeMachine backup prior to the date of the difficulty (late February) and dragged a January networkinterface.plist file to my library folder and restarted. I then had to reestablish the Networks: Delete then Add. Another issue was that I had Memory Clean set to open on startup (bought through App Store) and since this seemed to perpetuate the problem, I reopened in safe mode, started Memory Clean and then everything worked perfectly.

Thanks a lot!

I had the same issue of the App Store not recognizing my MacAir device (after loading the latest El Capitan, 11.5) and have tried every solution (must have been 15 or so, all kind of similar) but with no success.

I worked with an apple support person and we found that what was needed is to delete all of these 4 files below ( not just the first one, which is a popular solution that didn't work for me) and then restart.

Worked like a charm - Started right up, with WiFi working, and now the App Store allows me to connect to it and download apps.

Go to the files below and delete all 4
Macintosh HD/Library/Preferences/SystemConfiguration/NetworkInterfaces.plist
Macintosh HD/Library/Preferences/SystemConfiguration/com.apple.airport.preferences.plist
Macintosh HD/Library/Preferences/SystemConfiguration/com.apple.wifi.message-tracerplist
Macintosh HD/Library/Preferences/SystemConfiguration/preferences.plist

Restart and all should be in working order again.

THANK YOU SO MUCH! I have been looking all over the internet for a solution. It worked!

Been looking for a solution for the 'Your device or computer could not be verified' message. I found it.

Here's a little background: Because wifi and bluetooth suddenly stopped working it turned it in for repair. It was almost two years old, so it was still under 'warranty'. They ended up replacing the Logic Board. When I got it back I couldn't login to the computer with the password the store had chosen (1234) and written down to the technicians.

I ended up resetting the password of the account (https://coolestguidesontheplanet.com/reset-forgotten-admin-password-mac-osx/).

But trying to setup facetime and message + login into app store failed. One of the messages I got was the 'Your device or computer could not be verified'.

I upgraded to El Capitain, still with no luck.

I tried some of the suggestions made here, with no luck.

Solution: Then I ended up clean install El Capitain – but at the same time I logged into my iCloud from Safari from my MBP and then removed my Macbook Air from the list of devices. When I entered my iCloud settings during the install – everything worked fine... message, facetime, settings > iCloud, app store.

I don't think the clean install has anything to do with it. Removing my Macbook Air from iCloud from my MBP, then adding it again from my MPA – is probably what did it.

Hard rebirth...

This worked perfectly. Thank You.

This worked for me . Thanks.