how to make displacement in cycles to work?

Support Materials and Textures
1

I use cycles and displacement output, with mesh displacement type = “both”.

Sometimes, under hardly determined conditions, blender starts to ignore displacement completely, or to use some improper cached UV map for texture,
untill i create fresh new file and import all the objects and materials in it.
That sucks alot and i start to hate blender.

Do you know how it is possible to turn displacement back?
Maybe some internal caches to clean or whatever?

2

Cycles displacement is still experimental, will be fixed in an upcoming release (2.67 probably).