Cause:
This problem occurs when unloading and loading, with the loading operation performed quickly.
Troubleshooting:
Check whether the loaded program status bar on the teach pendant contains the program loading path.
Solution:
Reload the program.
Case sharing:
After unloading a program, quickly load it again. If the operation is very fast, the teach pendant's loaded path display has no program path. Editing the program and clicking Save at this point reports error 3821.