Board Thread:Lore Discussion/@comment-11345660-20130908095939/@comment-3573184-20130913005622

Sky Above,Voice Within wrote: I say they were bumped into another plane, simple as that. If they were, then Vivec would have been able to sense them, he could not.

Vivec makes it very clear the Dwemer are not in Mundus, any realm of Oblivion, Atherius, the void, or any outer plane.