App Store doesn't work on Mojave installed from scratch.

Something broke on Apple's backend. It's affecting almost every Mojave install, even those that haven't updated to Safari 14.0.3 or SU2021-002. You can work around it temporarily by killing the AppStoreagent process, then downloading again. Be advised that once you close the App Store, it will revert back to being unusable until you kill that process again.

Try this from Terminal " softwareupdate -l. " copy and paste without quotation marks. It should run the update check and return a list of Applications / System updates available. This command works outside of the Apple Apps Store so if it does not or error occurs - evidence to supply Apple Ticket Process

If you're comfortable working in Terminal, then do the following (taken from another website for brevity):

• Go to Finder and press ⌘ + Shift + G;
• Locate ~/Library/Caches/com.apple.appstore and delete com.apple.appstore which are cache files;
• Then press again those commands and go /private/var/folders, open each folder and each subfolder until you find com.apple.appstore and delete this folder;
• Restart your Mac.

Check the Apple Status Report Sometimes things are not working

Thank you very much for this helpful answer. Tried killing this process before.

Important information was that App Store has to be open before killing the process. And I‘ve to kill it twice. After that it started downloading! :-)

With App Store running, make sure you kill this process. Once killed, the download should function.

This only works for downloading the app. It does not work to update without removing the whole app and reinstall it again. (also I do not get any notifications when opening the Update page).

No updates in the Updates section, however when visiting a know ready to update app:

Restarted my Mac and tried again and then I could update... Still stupid -__-

At the bottom of this snapshot you will see Go to Folder ... SHIFT COMMAND G select that line in the Finder Go menu if for some reason hitting those three key simultaneously isn't working for you. Then you can follow the earlier instructions.

Clear the App Store cache after using the hack to update. Do you still get the notifications?

Yes, I did that. Multiple times. Thanks for the screen shots, but I knew what to do without seeing screen shots. :)

Checking the version of my installed apps against the latest version of the apps that are sending me update notifications, I see that I now have the updated version of the apps.

But I am still seeing two updates available on my App Store dock icon:

And I am still seeing pending updates in the App Store:

So I'm not sure why that's happening.

Thanks for the input, but that's not working for me.

⌘ + Shift + G doesn't work at all in either of the cases you say to use it.

I know how to find ~/Library/Caches/com.apple.appstore without using ⌘ + Shift + G, but I can't find /private/var/folders at all.

⌘ + Shift + G does not work for me at all. Nothing happens. I saw this technique described in a search, as well. I also saw people who responded to one such post who also said they didn't find /private/var/folders so clearly doesn't work for everyone.

I don't need you to hold my hand in any way whatsoever. No need to be rude about it and no need for you to respond to me further, thanks..

I'm not being rude. A simple search, both here or on most search engines, would have answered your questions. The way you wrote your initial as well as follow up question seemed like you were like the rest of those people too lazy to research for themselves.

If you're not that person, then forgive me. If you are, then I responded for the lulz.