Rasterize layer mask

Sound like plausible guesses, maybe the OP should post a screenshot including the pertinent Panels now to illustrate what they are actually talking about.

Or maybe you have a smart object with mask?

If you want to rasterize vector mask just press your CTRL/Cmd key and click on vector mask icon. Selection should apperars

Then remove vector mask and use Add Layer Mask buton in Layers palette to add bitmap, rasterized "normal" mask

pawel

Are you trying to make a normal raster grayscale layer mask from a vector layer mask?

What do you mean by »rasterise a layer mask«?

Layer Masks are pixel based, so no rasterisation is necessary.

Do you mean Layer > Layer Mask > Apply?