NX Check-out is not available until an edit is made.

Transitioning from NX11/TC11 to NX2206/TC14 Users are seeing different behavior with the Check-Out symbol in Teamcenter. The symbol does not display until the part is modified in NX where in NX11 the Check-out icon was Automatically displayed when opened in NX.

Check the Check-in/Check-out policy setting in the Customer defaults to see if the default is set to "Automatic Check-out on Modify or Save, Check-in on Save/Close".

The parts that are getting Checked-out are not Modified when it's opened in NX, the parts don't get checked-out till the part modified.