Sierra is not usable!

Back up your Mac if you have not done so already. To learn how to do that please read https://www.apple.com/support/backup/. To learn how to use Time Machine read Use Time Machine to back up or restore your Mac.

Then, shut down your Mac and restart it in "Safe Mode". To learn how to do that please read: Try safe mode if your Mac doesn't finish starting up. Compare how your Mac works in Safe Mode to how it has been.

Then, restart normally. If the same problem returns, please read the section If an issue doesn't happen in safe mode for Apple's recommended actions.

Finally, you can temporarily create a new User Account, and log in to that account to determine if the problem also exists when logged in to that Account. To learn how to do that read How to test an issue in another user account on your Mac. When you are finished troubleshooting, you can remove the temporary User Account by following these instructions: macOS Sierra: Delete a user or group. Before removing it, confirm you don't need any of the files you might have created in that Account.

Let me know what you determine.

Same here: the above plus photo damon. I don't need that! Like I did not need those U2 songs! Apple, you're on your best way to replace Mickeysoft!

So I rebooted in safe mode. It took a looong minute until the progress bar reached 100%. And then - nothing. I starred on the user logo circle for at least 15 minutes with this progress bar at 100%. Then I lost patience (to be polite). This is the very worst scrap coming from Apple. (I have a load of bad experiences which I have to hold back for the moment.)

Honestly, I do not have much hope to see a soon fix. The catastrophe only started with the latest update of Sierra. I need to re-install 10.11.

Did you post your reply under the different User Account? If so please log out and log in again under the same Apple ID you used to post your question.

I'm a different person, but have exactly the same issue. I'm about the throw away everything. It could hardly be worse.

I removed the PassKit framework temporarily. That killed passd and made System Prefs/iCloud available, but did not let me open Mail (that crashed). So I move it back and I'm at square one.

Now I just trashed /System/Library//PrivateFrameworks//PassKitCore.framework/passd

This (of course) did silence passd and it's no longer eating CPU. Mail works and iCloud in the Prefs is available. Calendar however is still crashing.

/System/Library//CoreServices/mapspushd was the next to go to trash. What a relief.

I'd be interested to know more about your Sierra installation. Did you upgrade an existing system drive? If so, had you previously installed one or more OS upgrades on this same drive?

Like every time (this is a MBP 2011) I upgraded via the AppStore. Yesterday it was a huge update with Number, Pages and some more. Also, I think I was not dreaming, it told me about a Sierra update. But today AppStore does not list this update any more.

Two of the buggers I removed were:

-rwxr-xr-x 1 root wheel 176368 19 Okt 11:09 mapspushd

-rwxr-xr-x 1 root wheel 1272624 19 Okt 11:38 passd

This night IDSKeychainSyncingProxy was running through at 100%. I Just started in recovery mode and performed a disk check (which reported errors that were corrected). It's silent at the moment, but when it starts looping again

-rwxr-xr-x 1 root wheel 162928 19 Okt 11:13 IDSKeychainSyncingProxy

will be the next to be removed. You can see that they have a rather new creation date.

As expected. When I came back, the last bugger was hogging on 100% CPU. I killed it and moved it to trash. I like that silence. Apple, please fix that mess immediately. And get calendars to work too! I have an app that uses EKEventStore which now does no longer find any calendar too.

Now that I removed that last bugger it seems as if I can't send mails any more. So I can choose between pest and cholera. Either have a CPU hog making my power supply company happy or use web mail. ***?

Now I was able to restart in safe mode. It did not change a bit. I read somewhere else that iCloud keychain synch is th culprit. That's indeed turned on. But I can't turn it off since the Prefs pane for iCloud simply hangs. I have no words for this situation, except those this forum automat will replace by asterisks. So just assume lots of asterisks right here.

Sorry you're having such a bad experience. It feels like Sierra is ****.

BUT since millions of people are happily using it the most likely cause is that some of ghe software that is installed on your machine is not playing nice withe new OS. Maybe it just needs an update.

You may run Etrecheck and post irs report here so we may be able to assist you more effectively.