PLEASE HELP!!! AE crashing immediately upon start up after last update.

This was happening to me also, but I was able to solve it. It was related to either my installed scripts or my layouts, I'm not sure which. However, the cause of my crashes may be different from yours so I suggest that you test via the following method. Whatever the result, please post more info here and help the community as the community is helping you. [Reference to forum member removed by Moderator.]

1. Find the folder on your computer that contains the preferences for After Effects. For Windows 10 it's located in the "AppData" folder for your user; I don't know where it's located on Mac OS. For instance, if you log in to Windows with the same user name as what you use here, it would probably be:
   
   C:\Users\satug\AppData\Roaming\Adobe\After Effects\
   
   
2. In that folder you should find a folder called "16.0" for the latest version of AE. If you rename that folder (I'll call it "16.0_HIDE" from here on)
   
   
3. Start AE. A new folder and preferences will be created by AE in the same location.
   
   
4. Did AE crash?
   • If yes, then you can probably be sure that it's not your preferences. Keep a copy of the folder you renamed ("16.0_HIDE") and give Adobe a call. Let us know what solves the problem!
   • If no, continue to step 5. This is what you're hoping for...
     
     
5. Before you continue, close AE. Because AE crashed with your preferences but not with new preferences, you know it's something in that folder! The rest of this process can be tedious, but you have to be methodical about it.
   
   
6. In order to determine what caused the crash, the old preferences need to be tested one item at a time. This means that you're going to copy a single file from the old preferences - "16.0_HIDE" - to the newly created folder - "16.0" - and start AE.
   
   
7. Did AE crash?
   • If yes, you know that's a problem file. (There may be more than one!) Move the problem file to a different folder such as your desktop. My suggestion would be to keep it for troubleshooting; you may want to send it with a bug report or open it up to see if it's reparable depending on what the contents are.) Continue to step 8.
   • If no, close AE and continue to step 8.
     
     
8. Copy another single item from the old folder to the new folder, then start AE. Go back to step 7, above: Did AE crash?

Best of luck!

You didn't really provide much information.

Did you start the project in a previous version? If so it could be something a simple as a plug-in that needs updating.

Also I believe both app versions need to be the same for dynamic link to work but I may wrong about that.

If you're on a schedule you might just want to revert and hope the file is backwards compatible.

If you did update in the middle of a project then you just learned a huge lesson the hard way.

Never do that.

satug  wrote Any suggestions besides reverting to the old version?

Nope.