After upgrade to MacOS Mojave, I cannot login or connect to App Store.

I seem to have the same issue. Here the two lines from system.log. Maybe somebody can make sense out of it...

Sep 30 19:09:37 iMac App Store[794]: DEPRECATED USE in libdispatch client: dispatch source activated with no event handler set; set a breakpoint on _dispatch_bug_deprecated to debug

Sep 30 19:10:01 iMac App Store[794]: objc[794]: Class ITNSImage is implemented in both /System/Library/Frameworks/iTunesLibrary.framework/Versions/A/iTunesLibrary (0x7fff8f217568) and /System/Library/CoreServices/SetupAssistantPlugins/iTunes.icdplugin/Contents/Ma cOS/iTunes (0x10f22e7c8). One of the two will be used. Which one is undefined.

Just wanted to post an update, that I did an application cache clean today with a PRAM reset. While I wasn't having any issues. It does feel like it has smoothed things out.

I noticed that clearing cashes deleted my exiting installed updates list for the App Store, but it still functions as normal.

I have this problem too, not only with the App Store but also with Apple Books (book store). Same issue, cannot log out and cannot open the book store ( internet connection required). I do not have problems with the iTunes Store. More of you who reconize this also?

I should have asked this earlier, but those of you having these issues with Mojave and the App Store, etc are you having any issues with iOS 12, on your same connection? Just curious if there is any sore of connection.

OK, that's good. I wasn't having issues on either of my iOS devices. As you know I fixed my glitches on Mojave. Was more thinking since iOS, TVOS, and macOS share some of the same internals, that it could be a bug there. Since not, sounds like it's related to the Macs more specifically.

When Mojave works, it feels like a very nice ride. Hope Apple speaks up soon.

One of the hard things I find about helping on forums is you usually don't know the people directly, and can't handle the setups for myself. So I only have what the people say to go on. In this case though it sounds like Apple knows about this issue now, and it doesn't seem to be a specific group of people affected with any specific setup circumstances.

This isn't a question directly in line with the topic of this thread, but, is there a way to contact Mods here?

I was reading that they are the only ones that can change a username, and I would like this one changed to one of my nicknames I use on a more consistent basis. I created this years ago, and I don't even remember why I picked this name.

I was able to get the App Store to work by booting my Mac into Safe Mode (hold down the shift key until you see the Apple logo). Right now the App Store only works for me in Safe Mode so there's a conflict someplace. After I boot back into normal mode my MacBook once again cannot connect to it.

Neither using my Admin account or signing in, in Safe Mode, worked for me. It looks like I'll have to wait for Apple to fix this problem. I'm convinced that in my case, there are remnants of the old App Store on my drive that for whatever reason were not cleaned up during the installation process.

So I created an additional ADMIN acct and App store works great in that account, when I go back to main acct back to same issues everyone is having here. There must be a way to see differences in accts to see what need to be modified.

The first step is to check for connection, check your connection via iTunes Store and if it works means your connection is fine. If it is an update then this happen more likely the update has some flaws. Do a reinstall of the Mac OS of course before that backup first.

Same problem here.

I create a new admin account with my Apple ID, same problem.

When I run the App Store application, I just see "Cannot connect the App Store" with a button "retry". What's really strange is when I click on the Store menu, I get nothing at all.

At this point in time, I think we have tried everything possible except a clean install. So all we can do is wait for Apple to come up with an answer. I for one won't drop this if I don't hear soon. This is my work computer, and in some form it is creating a problem for me. For one, I got into trouble for creating another account. This network I am on is a secure network, and a secure location. So I had to remove the second account. At least I didn't lose my administrator account.

Little Snitch (my third party network filter) issued an app update today that correct the problem with the app store invalid code signature. After restarting both my mac and the app store app, my ability to connect to the app store has been restored. I'm a happy camper again!

I hope everyone struggling with a different app store issue than mine find an equally quick fix.

Reinstalled macOS and have the same

exact issue. I’ve tried all suggestions posted in this forum and have not resolved the issue. It seems like the only option is to do a clean install, restore files from back up and not restore system settings. I think that’s overkill because it seems like a networking configuration issue on the app side that might be resolved by fixing a file or configuration setting.

 needs to address this since it seems like a common bug.

I actually still have a second admin account that I had set up and used only during installation of this new iMac last year. I had not used this account since this then.

I could sign into the App Store and install both new software and updates (e.g. XCode 10) without any issues. Going back to the other admin/user account, ... same issue as before. No sign-in possible. At least, I have my updates now. Books is still an issue, though. Cannot get my new book, that I bought on the iPhone (iOS12) this week.