Trying to system software but get following error message "The operation couldn’t be completed. (NSURLErrorDomain error -1012.)(-1012)

intheclear: that seems to have worked...

Indeed. @intheclear is very right. Follow his instrucction. Work like charm!

worked for me as well.

1. Open System Preferences - Network

2. Highlight active connection

3. Click Advanced.

4. TCP/IP

5. Renew DHCP Lease

sadly the suggested fix for renewing the DHCP lease did not work for me. I'm still receiving the same error.

Try turning your antivirus software off.

Same here looks like it is an issue from the App Store hope it gets fixed soon

I'm having the same Issue as you 😟 it's on Apple Side, they need to fix it. 🙂 i just now Purchased something from The Apple Mac App Store & i ran into this Issue also 😟

Same error here on all the Macs in my house. I had my Father try as well at his location and he's getting the same error. Looks like an issue with the app store.

Is anyone running Kaspersky anti-virus (or any other AV) software?

If so, turn it off before attempting to download anything.

No AV software. I tried on 3 different machines at my house and my father who is using a different ISP is also getting the same error on is iMac..

Unfortunate - all the other threads I found had the AV software as the culprit.....

I don't have any AV software installed. The problem is on Apple's end. The problem occurs on all my machines and all my boot drives.

It appears that the certificate for the app store site was allowed to expire; which may be the cause of the problem. If that is the case, you'll have to wait until Apple renews the certificate.

I got this just hitting update there:

will have to see what Apple say's after the weekend

Yep - seems there are more and more posts about this.