So, I have a project open with just a single clip in the timeline and it renders in the background. Then I close the project. Then I open it again, and it starts rendering that clip again. But it already rendered?!?! Does it need to keep re-rendering like that? Or is there something I might be doing wrong? This clip is long and takes about 40 minutes to render. So I'd prefer if I didn't have to render it every time I opened the project :)

Thanks for the help!

...Does it need to keep re-rendering like that? Or is there something I might be doing wrong? This clip is long and takes about 40 minutes to render. So I'd prefer if I didn't have to render it every time I opened the project :)

Thanks for the help!

The only time I've had to re-render is when the render did NOT fully complete to a green slice. Once it's rendered, it's good.

You may want to check your settings to make sure that the timeline properties and the clip properties match.

Sounds like something is wrong.
Obviously it depends what it is but 40 minutes is a long time to render.
And no, it shouldn't need doing twice if it finished rendering the first time.

Ah so it has to render to a green slice to be fully rendered. OK. I was seeing yellow and thinking that meant it was done. Thanks! It's good now. The learning curve continues!

You've got it!
Liquid renders in the background so you should be able to continue working whilst rendering takes place.
Yellow slices means that you can view the footage whilst it is rendering. Red slices means that you can't. Green means that rendering is complete.
It's worth keeping an eye on the Pinnacle forum too which is excellent.
But do post here too if you have any more questions.

Ah so it has to render to a green slice to be fully rendered. OK. I was seeing yellow and thinking that meant it was done. Thanks! It's good now. The learning curve continues!

Very good. Another thing to keep in mind is that you can change your Render drive to an external drive if you your working on a big project...and it's important to make sure that drive is turned on or Liquid will change your render location.

That happened to me today...I opened up liquid and it started to re-render. Since my external drive was not on, Liquid changed the render drive to an internal drive. Once I figured it out, I turned on the drive and changed Liquids settings back to the original render drive location and all is well.

When I'm done a long Render, I always FUSE it to a single file to free up resources and backup the file on another drive.