Upgrade to 16.1 resulting in odd error for certain projects

I had the same problem in AE 18.4.1 using Big Sur. I had to roll back to 18.4 to fix the problem.

I have the same issue with the latest After Effects update. I think it's related to a RedGiant effect. But it basically renders the project file useless. I tried restarting my computer, the program, redownloading AE, etc. This is very frustrating. Any solutions?

I am also having this problem! It has returned!  

same problem here, except mine with an image lounge resource. I have had this with other effects as well. the project opened earlier today, no image lounge effects have been added. Ican't reimport it. etc. I had this problem at least before in the last year. just updated to lastest AE, tried again. no luck. can't open any of my recent autosaves either. I think uninstalling and reinstalling plugins worked before, but this problem has been around and involves many plugins, which I don't believe are even used in the project. It seems to me to be an issue worth addressing.

I've just installed an update from RG (using Red Giant Link). Image lounge & Composite Wizard now working fine.

Solution that worked for me:

On Mac went to Applications > Adobe After Effects CC 2018 > Plug-ins and moved all of the plugins out of there (save them in another location).

How I got the error in the first place: I had a project I was working on (AE 2019). Someone else that had worked on another project from an earlier version (2018) had a composition I wanted. When I imported their comp, it all worked fine so I thought I was good to go. I worked, saved and closed out. When I went back to work on my project that had the imported comp, I get this error in the original post. My suspicion is that since the imported project was an earlier version of After Effects it was trying to essentially open up two versions of After Effects at once. Maybe?

Regardless of how exactly, taking out plugins seemed to do the trick. In my case I had a trial of Boris Effects (they are called CC in the effects pane) so I was able to get rid of them and not need them back. I guess if you needed the plugins that you're taking out, perhaps you could put them back in one by one, open the project and check to see which is the offending one.

I hope this makes sense.

Same thing happened to me today. Hopefully swtiching back to 16.0 does the trick.

I'm having the same issue..adobe instructed me to update the plugin, but same issue as everyone here

Also having this issue. Downgraded to 16.0.1 and they open now... but having to upgrade to 16.1.0 when i need to open newer projects using the new features (content aware fill etc...)

If there anyway to have them both installed so i don't have to spend all day up/downgrading???

Seems to be an adobe issue not a RG issue!

I'm having this problem as well and the comp doesn't have any Red Giant plugins used on it but I do have the entire RG suite including Universe installed. For now, it seems I can click Ok and the file opens. I'm also running Animation Composer, AE Juice and Motion Factory in case any of that helps fix it. Thanks!