[Gabriel Netto]

Same here!
Sierra 10.12.1.
after CC
This is horrible!
had to do a quick export and forgot one missing layer… I have to wait till it finishes to re-export… imagine if it had 3D…

[Gabriel Netto]

Dear 86::2 error (4) fellows:

THIS SOLVED THE PROBLEM FOR ME.

It seems to be (at least on AE 12 CC) a conflict with DVCPROHDVideoOutput QuickTime component.

I’ve just find this on adobe’s website:

This problem occurs because QT32 Server, the process that After Effects uses to read and write QuickTime files, is crashing. One cause of QT32 Server crashing is a bad interaction with the QuickTime video out system when the Apple DVCPROHDVideoOutput QuickTime component is installed.

To work around this problem, do the following:

1. Go to [OS Drive]/Library/QuickTime.

2. Make a backup copy of DVCPROHDVideoOutput.component by dragging it to the desktop.

3. Now delete the DVCPROHDVideoOutput.component by dragging it from the Library/QuickTime folder to the Trash. Enter your password when prompted.

4. Empty the Trash. (This is an important step. Don’t skip it.)

Note: A couple of users have reported that, instead of the above instructions, installing the Apple ProApps QuickTime Codecs 1.0.2 update (https://support.apple.com/kb/DL1396) fixed the problem for them. You may try this solution first, though when we tested this it did not resolve the problem. We noted that the version numbers of the DVCPROHD component files were not incremented by this update.

Link: https://blogs.adobe.com/aftereffects/2013/08/solutions-for-problems-with-quicktime-files-in-after-effects-cc-12-0-because-of-conflict-with-dvcprohdvideoout-quicktime-component.html

Hope this helps you too as it did for me… (my deadline is today!)

Cheers!
Gabriel