When you upgrade a Mac OS (as opposed to installing the new version fresh), Mac OS will _often_ set permissions of folder and files incorrectly.
You'll see this problem in programs like After Effects in the form of error messages saying that a file can't be written, overwritten, or renamed.
To fix this in the case of After Effects, go to the preferences folder and set the _entire_ preferences folder and all of its contents to be writable, not read-only.
By "preferences folder", I mean whichever of these is relevant for your version:
/Library/Preferences/Adobe/After Effects/10.0/
/Library/Preferences/Adobe/After Effects/10.5/
/Library/Preferences/Adobe/After Effects/11.0/
/Library/Preferences/Adobe/After Effects/12.0/
/Library/Preferences/Adobe/After Effects/12.1/
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Todd Kopriva
After Effects quality engineering kopriva@adobe.com 206.675.7931
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