Unable to make a Sketch external from an Extruded or Revolved feature.
Solution
If the Sketch has a child feature that includes a Mirror or Pattern Feature, the Sketch cannot be made external. This is as designed.
Notes and References
Hardware/Software Configuration
Platform: all
OS: n/a
OS Version: n/a
Product: NX
Application: DESIGN
Version: V11.0.2
Function: SKETCHER
Ref: 001-9319137