As above. It crashes the entire program without error message. Have tried to search google, but no mention of this.
Help!! 
Are you using ZBrush 4R7 P3?
Are you using the 32 bit version or 64 bit?
What are your system specs? How much RAM do you have?
How complex is the mesh you’re trying to Remesh?
Have you seen these tips and tricks for using ZRemesher: http://docs.pixologic.com/user-guide/3d-modeling/topology/zremesher/tips-and-tricks/
I’m using ZBrush 4R7P1 I think. It crashes only when remeshing on Z axis. I’ve tried doing it on the standard 3DCube, and it stills crashes… Bug?
You should update to P3 