Solid Edge Checkout option is showing in native mode at the top of pathfinder.

Opening an assembly in native solid edge, in pathfinder window showing "check out by you" actually this is shown in manage mode.

This was a part specific issue , below steps helped to overcome the issue.

Open the data and make it available using RMB on asm--File Properties--SE Status--Click on three dots (...)

 Available option will be enabled for the user who is the owner of this asm/part.