How can I rename a footage .ai file for AE without breaking the references? I've got a composition in After Effects CS 6 on Windows that contains several .ai files. One of them has over 30 layers, which I imported and animated in AE. Unfortunately, I gave the .ai file the not so clever name foo.ai because it started out as a test but worked, and I'd like to go ahead with it. When I rename the file to something more sensible, like Scene 1 - Spaceship.ai, AE complains about a missing footage file. Now it wants me to give it the new path, which I do. I have to select the layer from the .ai as well. And it looks like it wants me to do it for every layer from the same file.

I've already tried making a copy of the AE project file, opening it with a text editor and replacing all occurrences of foo.ai with Scene 1 - Spaceship.ai. After that, AE told me it tried to read after the end of file. Looks like there's a file length in there. Damn.

So how can I do this without having to change the source file and resellecting the layer for each individual layer in AE?
Save the project in XML file format, do as you already did, open it in a text editor, find-replace the name. Open the modified file in AE and re-save it in its normal binary format (aep).

Size shouldn't be an issue since renaming a file doesn't change it size. It seems like you have edited the aep file? Hope this helps!

More on the topic here:
http://help.adobe.com/en_US/aftereffects/cs/using/WS3878526689cb91655866c1103906c6dea-7fa0a.html