Here's the first thing to try:
When you upgrade a Mac OS (as opposed to installing the new version fresh), Mac OS will _often_ set permissions of folders and files incorrectly. To fix this in the case of After Effects, go to the preferences folder and set the _entire_ preferences folder ( /Library/Preferences/Adobe/After Effects/12.1/ ) and all of its contents to be writable, not read-only.
I am getting the exact same error message and crash when I try and open AE 12.1. The crash always occurs at the same place, i.e. when "Cleaning EMP" occurs on the splash screen. I tried setting all preferences for AE 12.1 to read and write, but that did not help. I have repaired all permissions. I have created a new account and tried to open AD 12.1, but I still get the same error message. I have tried two uninstalls and reinstalls, but that did not help.
I notece several other posts reporting this exact same error message.
Any other suggestions?
As I posted above, I am experiencing the same crash on start-up problem with AE 12.1 on a Mac Pro running Mavericks. I have tried everything I can think of to solve the problem including numerous reinstalls, etc. The problem of the crash occurring everytime I try to open AE CC (12.1) remains and it always occurs at the same place in the program startup, i.e. when the splash screen reports that it is "Cleaning EMP". Like you, I also have AE from CS6 installed and updated, and it opens with no problems. Furthermore, I have AE CC 12.1 intalled on my mid-2012 Macbook Pro with Retina Display, and it opens and runs fine on that machine. Thus the problem is specific to my Mac Pro 8-core machine. However, I have tons of software installed on this machine including the CC suite and everything except AE 12.1 opens and runs fine.
I filed a ticket on this problem last week and spent an hour on the phone with an Adobe tech support person, but he could not solve the problem At his request I sent him the crash log and I am still waiitng for any response. The ticket remains open.
If you find a solution to this problem that we are both having, please let me know and post here what it is. I will do the same.
I have exactly the same problem with AE CC posted at the top of this thread. I filed a ticket with Adobe and spent an hour last week with a Adobe Tech support trying to solve the problem wihtout success. I have received no response since last week to my filed tech support ticket. The solution posted by Todd did not help.
Is anyone else having this issues with AE 12.1? If so, have you found a solution.
Since AE for CS6 is installed and working on this Mac Pro, if this problem with Adobe AE CC on this machine is not rectified I see no reason to continue to subscribe to CC.
I was able with the help of some excellent tech support from an Adobe tech suport person to solve the problem of AE CC not launching on my Mac Pro. After working with this person for almost a week and literally trying everything we could think of, it was necessary to completely uninstall every single Adobe application on this Mac Pro. Note over the years on this Mac Pro I had previously installed CS3, CS4, CS5, and CS 5.5 Production Premium Suites. All had been removed using the provided Adobe uninstaller before installing the CS 6 Production Premium Suite about two years ago and the Adobe CC Suite in May of this year. Somewhere in the files left behind by those uninstalls of previous Production Premium Suites was something causing AE CC to fail to load always at the same point (i.e. "Cleaning EMP" whatever that is) and display the exact error dialog box that you reported.
I might add that without extensive help from my Adobe tech support person, I would never have been able to locate all the Adobe files left behind after uninstalling both CS6 and the entire CC on this machine. It literally took us hours to locate and delete all the files not removed by the Adobe uninstallers for this software.
Once all traces of Adobe files had been removed form this machine, I then downloaded and reinstalled AE CC via the Creative Cloud app, and it launched and runs perfectly on this machine. I have now downloaded the remaining Creative Cloud programs as well as gone back and reinstalled CS6 Production Premium from the purchased DVD that I had on hand. I then updated all CS6 programs via CC, and now all Adobe applications, both CS6 and CC launch and run with no problems.
I should add that the Adobe tech support person told me that uninstalling all Adobe files on my computer was a last ditch extreme measure to get AE to run on this machine. However, the fact that it worked seems to me rather strong evidence that some Adobe files left by old installs of Adobe software created the problem with launching AE CC, and not any problems with Mavericks.
I have exactly the same problem on a dual quad core 2008 Mac Pro. AE CC used to work. I was using it, even with dev level versions of 10.9 and 10.9.1 In the last week CC has been pushing a lot of updates out and I cannot tell precisely when it broke, but it is broken now.
I have done the file permissions thing, uninstalled, manually removed old folders for long uninstalled versions from the Library, reinstalled and I get the same issue. I've had the Mac Pro for a while, I mean there were folders that the uninstallers left behind in the Library from CS2. I also disabled my Matrox device because of course Matrox has no drivers for Mavericks and has no idea when they might get around to creating some.
Fortunately I did not remove CS6 (and sure won't be removing it) because it still works as it is supposed to. Unfortunately, any projects I push out of AE CS6 for Premiere Pro must be opened in PP CS6 because PP CC cannot find most of the named effects in the project in AE CC (that's a whole different kind of dumb).
In the short term I can work in CS6 but that there is no clean solution to this problem, plus that the application worked before indicates that the bug is in AE CC somewhere. I have Mavericks 10.9.1 on my other machine (Macbook Pro Retina) and AE CC 12.1 and 12.2 work there. In this case I chose not to migrate my settings when doing the update to 12.2. I don't know if that makes a difference. It would appear that many of us experiencing this problem also have Mac Pros as a common denominator. Perhaps Adobe could look at what makes the older machines different in how AE interacts with them.
I solved my problem. My solution may help others.
Examining the logs for the crash showed that thread 0 was the one crashing. Digging in, I determined that in my situation it was related to a Matrox VPG something or other. Even though I had disabled my Matrox device it wasn't enough. I pulled the latest download and ran the uninstaller for the current Matrox drivers, the ones that don't work in Mavericks, regardless of release. The uninstaller did what it did and required a reboot.
The machine came back up and after logging in, I clicked the AE logo in the dock, same as every other time, and it loaded up running through the usual checks and actions. In the past the crash would come at Cleaning EMP. Now the application starts up just fine. Note that the Matrox card is still in the Mac Pro and the box is now connected to the card again, but as there are no drivers, there's no one home there. I guess over the years of updating Matrox drivers something didn't uninstall properly, although I credit Matrox that while tedious, their upgrade process usually works.
It looks like because the Matrox drivers were fighting with Mavericks and even indicated functioning, they were really putting the blocks to AE on launch. If you have, or have ever had, installed a Matrox driver and you are using Mavericks, you might want to try uninstalling it completely.
Hopefully this fix will help others.