Delete the Shell mesh or use the Undo button to clean the model up to get rid of the shell elements created during the previous step. Now mesh all the volumes using the default mesh settings. This is what happens during the mesh process in Integrated Mode only this time you will have visual clues as to what may be the problem.
Check for errors that may pop up. Pro/MECHANICA Independent Mode will highlight areas that have a problem. Look at these areas but do not use the Ctrl-Mouse keys to change the model view. Use the F2 (rotate), F3 (pan) and F4 (zoom) along with the left mouse button to change the model view. Some of the geometry or features will be put into special groups. These groups are similar to Layers in Pro/E and may be turned on and off. You may also stop the mesh process at any time using the Ctrl-C keys. This will allow you to look a a partial mesh.
If no errors are reported, look at the mesh for dense populations of elements or points. This would be and indication of some geometry errors or small features that the mesher must deal with.
Possible solutions may be to de-feature the offending geometry, recreate the geometry in Pro/E using a different technique, fudge the geometry so that it is approximately the same but not exact, try an IGES or STEP file round trip into Pro/E or repair the geometry in Independent Mode and run the model there.
For models that don't mesh or take a long time to mesh you may be able to tip the scale a little by adding seed geometry like datum points, surface regions of volume regions. This may be enough to help the mesher out.
