Moving multiple compositions in one main composition - ERROR message

Found it. I got the same problem as you.

Steps :

1.Go to File and Select Dependencies and choose Collect Files.

2.It asks you to save in a dialog box and select Save.

3.Then make sure Collect Source Files is selected as All.

4.Click Collect and just Save the folder.

You're Welcome

"After effects warning: already used as an embedded comp for media replacement" FIX

I was facing the same problem with my project.

I created an Illustrator file and imported it to after effect and it created a folder with all layers and comp with all layers in that as order.

but when I try to import that comp which is made by illustrator file into another comp this error message pops in.

I did not find any logical explanation for it but I found a solution.

solution:

duplicate that comp in the Project panel and delete the first one if you want the import duplicated comp.

Without any specific info about the timeline and overall project structure we can't really tell you much. Simply sounds like there is a cyclic connection, i.e. one of the comps you are trying to move is used in another sub-comp already. Other than that it could be some of that nonsense garbage like master properties, advanced compositing options, Essential Graphics or some external DynamicLink connection getting in the way and also create some weird dependencies. These days AE is overloaded with this crap and it always gets in the way. A good place to start would be to switch to the composition flowchart and check where there may be overlapping/ branching connections when there are supposed to be none. Otherwise a lot more info is needed such as screenshots, info about the source media used, system info and so on.

Mylenium