Just a simple...

move file all about (.rpm) from
C:\Program Files\Adobe\Adobe After Effects CC 2019\Support Files\(Media Core plug-ins)\Common

to

C:\Program Files\Adobe\Adobe After Effects CC 2019\Support Files\(Media Core plug-ins)

and done...

Hope this helps

Try renaming the dynamiclinkmanager.exe file that is located in your
C:\Program Files\Adobe\Adobe After Effects CC 2019\Support Files to ex.

"DynamicLInkManager_backup.exe". Then try opening up AE CC 2019. This should let you get past the initializing MediaCore stage

There is something wrong with connecting to the Adobe Dynamic Link Manager CC 2019 Process upon startup. It takes a really long time for some reason.

It works perfectly in AE CC 2018. The Adobe Dynamic Link Manager CC 2018 Process loads up right away allowing the program to launch right away. No freezing on the Initialize MediaCore stage

Hope this helps

Thanks Andreas... following comment workd....

Andreas Toth commented · November 4, 2018 10:08 PM · Flag as inappropriate
I renamed C:\Program Files\Adobe\Common\Plug-ins\7.0\MediaCore to C:\Program Files\Adobe\Common\Plug-ins\7.0\MediaCore.disabled. This resolved the issue. Obviously a plug-in is incompatible. Suggest After Effects detects that it has hung loading a plug-in and suggests to disable it instead of hanging like this.

WTF!!!! I was working on project on friday and it was working fine.
This morning I open After DEFECTS and it refused to ram preview.
Then it froze. Now it refuses to even show a start up screen.
I wish adobe would stop using us users as their debugging solution.

I had this Issue . I eneded up downloading the latest Windows Media Feature Pack and it fixed it

https://www.microsoft.com/en-us/software-download/mediafeaturepack

I hope this will be helpful to someone else: I was experiencing the same issue of AE 2019 getting stuck on the launch screen at "Initializing Media Core" but none of the fixes listed below were helping. Talked through with Adobe support and nothing came out of that either. Ultimately, I ended up rolling back a driver on my laptop's integrated graphics card (it was an Intel(R) UHD Graphics 630) and lo and behold and that seemed to do the trick. Suggesting this in case it will cure a headache for anyone else.

I tried what Andreas said with renaming the Media Core folder but all that was in that folder was a text file that says "Dummy" inside it says, "#Dummy file installed in the MediaCore folder." Any ideas?

Having the same issue. Can't seem to find a fix...seems to be related to the Quicktime update they did in 2019 16.0.1. The original 16.0 version of AE 2019 works great.

Wondering if there's some error with the plugin they made to make Windows read/write prores.

For me moving plugins out of the folder:
C:\Program Files\Adobe\Adobe After Effects CC 2019\Support Files\(Media Core plug-ins)\Common\
- worked. Offending plugin is either ImporterWave.prm or maybe ImporterQuicktime.prm, at least the program is now starting up.

I also had the same experience, after updating to AE 16.0.1, always crash when opening AE, and crashed at the same place, MediaCore. Hope they will fix this issue

It should show up the plugin name if it hangs, in the loading screen

I renamed C:\Program Files\Adobe\Common\Plug-ins\7.0\MediaCore to C:\Program Files\Adobe\Common\Plug-ins\7.0\MediaCore.disabled. This resolved the issue. Obviously a plug-in is incompatible. Suggest After Effects detects that it has hung loading a plug-in and suggests to disable it instead of hanging like this.

Uninstalled and re-installed After Effects 2019 resetting settings. Did not help. Installed latest 2018 version next to 2019 and 2018 version runs OK yet 2019 version won't run. This on Windows 10 Pro Insider Preview version 1809 build 18262.1000.