Rotobrush error

[Илья98C6]

Hello, I have a problem with Rotobrush tool.  I used it on a clip, freezed the result and everything was good, until one moment without a reason it stopped working. There was no error message or anything, The layer just displayed as original regardless of the applied effect. I tried to unfreeze the propogation, but this button is no longer clickable (I attached the screenshot). All the foreground and background strokes remained. 

I also tried to copy this effect to duplicated layer, but it produces quite a different result and still requires a lot of refining work. The shot is hard and long and I don't really want to do most of the work again. 

I would be really glad if anyone could help me with this issue

[Rick Gerard]

Try this:

• Trim your video to include only the frames that will be in the final edit
• Create a new comp that only contains the trimmed footage and name it Rotobrush
• Pre-compose the trimmed footage layer moving all attributes and setting the comp to the length of the time span of the trimmed layer
• Open the Rotobrush comp in the Layer Panel and run Rotobrush, then freeze and make the adjustments you need to make in the Effects Control Panel and Freeze Rotobrush
• If the Rotobrush takes longer than a few minutes, use the Composition menu to Pre-render the Rotobrush comp

With only one layer with Rotobrush applied in a comp and the footage trimmed and pre-composed, Rotobrush will have more access to system resources. You have a better chance of having a problem-free workflow. Rendering using the Composition/Pre-render menu will replace any instances of the Rotobrush comp in the project with a production master video that has an alpha channel. You can then delete the original Rotobrush comp, reduce the Project File size, and have everything you need to complete the project.