Extruding issues

[jatNGV77]

I have derived an Iphone from a rectangle. I now wish to make an Iphone case. I can't extrude sections for volume buttons, charging ports etc. as it only gives me the option to create a 'new solid'. A few students in my class are having the same issue, but not all. Please help!!  Attached is my file.

[RobSinglehurst · Accepted solution]

When you Delete the faces use the "Select Lump or Void" option in the dialog box, this will then leave the part as a solid so your extrusion cuts will then work. 

[jatNGV77]

Perfect!! you solved my problem.

Thanks so much!

Jayden