In CFX-Pre, if you choose to view the meshes by region type (by right-clicking on Mesh in the tree view and selecting View by > Region Type), then if you select one of the mesh assemblies and try to delete it, all the assemblies are deleted.
CFX-Pre is not correctly identifying which assemblies were selected.
The "Undo" functionality will put back all the mesh assemblies if these are deleted accidentally.
A single mesh assembly can be deleted as follows:.
a) In the View by > Region Type view, a mesh assembly can be deleted by selecting all the 3D regions within that assembly and then using right-click over one of these 3D regions and choosing Delete Mesh.
b) A single mesh assembly can be deleted in the ordinary Outline view or in the View by > Source File by right-clicking over the name of the item to be deleted and choosing to delete it as normal.
ANSYS CFX 11.0 Update 1.