MacOS – Re-applying ComboUpdate to Sierra after later SecurityUpdates are installed

In a few cases where the code signing allows, you can prevent this check.

• In finder, right click each app and show package contents.
• Locate a folder named _MASReceipt and delete it.

This removes the receipt that tells the App Store to manage the app. I would do a backup of all apps before you alter them in case you want them back without downloading the update you seek to avoid.

In many cases, this wrecks the app since it’s now been tampered with - How do I avoid update checks for third party software (cobook), dont want to "update" by mistake

The long term answer is to have the developer code sign their app in a manner that lets you can opt out of upgrades. Once you convince them why this is good, they will have the option to fix whatever issues you have with patching the app or allow their customers to control this.

I like to remove the network interfaces entirely if someone manually delete plist files or changes things in the library directly and then restart to give the system a chance to recreate the files if it can. Especially on Sierra and later since the preference files aren’t canonical in most cases and the settings persist in a database and get flushed back to disk periodically when the defaults system commits a change.

1. Remove WiFi interface from all locations (if you have network locations)
2. Restart
3. Add in the wirelesss network connection in system preferences

If that doesn’t work, next is two items. You may want to check the network with another device or two - the Mac update could be coincidence and not causal. If the network is working, then you’ll want to look at things other than the core os.

Firewall (little snitch), anti virus (eset or Kaspersky), vpn software and anything that adds extensions or network modifications.