It's hard to say what is going on without the details of your project and your render settings. What's changed from other projects?
I Haven't changed anything from what I normally do. What info would you need in order to help?
What changed on your system? Any software or driver updates? Will one of your old projects render properly? Is your software up to date? What is happening in the comp? We need details. What are your render settings?
i recently got Yosemite for my mac but that shouldn't affect it. no software or driver updates. i opened another project and it rendered that one fine. When i first started with this new project it would render fine then one time it just popped up and i couldnt pre render for more than 6 seconds. just opened the new project and it would only pre render to the same 6 second mark. my render settings shouldn't matter because it is just pre-rendering right? im on quarter quality if that helps
What effects are you using in your project?
What assets/footage do you have in the project?
What is the exact version number of your AE? If you're using CS5.5, it should be something like 10.5.x
i recently got Yosemite for my mac but that shouldn't affect it.
Au contraire! AE CS 5.5 DOES NOT WORK PROPERLY with Yosemite. Furthermore, Adobe has no plans to make it work with Yosemite because CS 5.5 is three versions out of date.
Your options: get a newer version of AE or revert to the previous OS. That's it.
And it you counter that AE's worked okay before even though you had already updated to Yosemite, here's my response: you got lucky. Yout luck has run out.
Gah! I can't believe I missed that. Yeah, CS5.5 will not work properly with Yosemite. We've had lots of (very varied) issues on these forums from folks who were, like, "It worked fine before on Yosemite, but now it's not." Well, then you got lucky for a while...