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Identify the exact block number where retrace was attempted from the alarm history and program display.

Review the program block and surrounding lines for M-codes (especially M06, M98, M99), G65 macro calls, or custom cycles that are active at the restart point.

Move the restart point earlier in the program to a safe position before the problematic command, or restart from program beginning (sequence number N0 or block O-number).

Ensure tool offsets and work coordinate systems are properly established before resuming machining

If restart must occur at this location, use MDI mode to manually execute necessary preparatory commands, then restart from the next safe block.

Check if the restart block is located after a work coordinate change (G54-G59), plane selection (G17-G19), or canned cycle that was initiated earlier.

Verify that essential modal commands are present in or before the restart block. Add explicit modal commands (G00/G01, G90/G91, G54, G17, etc.) if needed.

Enable 'Background Edit' or 'Program Restart' parameters if available (consult parameters 3107, 3109, or restart-related settings for your specific Fanuc model).

Changing parameters requires proper authorization and backup of current settings

Perform a 'dry run' or 'machine lock' test of the restart sequence to verify the control can properly retrace without axis movement.

Search the program for macro variable assignments (#100-#999), conditional statements (IF[], WHILE[], GOTO), or computed values that affect the restart block.

Review macro variable values in the macro variable display screen and manually set critical variables if they affect the restart position.

Document original variable values before making changes

Simplify the restart by moving to a block before conditional logic begins, or after the conditional section completes.

Consider restructuring the program to minimize macro logic in critical restart areas, or add optional stop points (M01) at safe restart locations.