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Review the part program at the alarm line number and identify the retrace command (typically G26, G27, or custom G-code depending on control version).

Verify that a valid cutting path exists immediately before the retrace command and that no program reset or M30/M02 has cleared the retrace buffer.

Check parameter settings related to retrace buffer size (parameters vary by control model - consult maintenance manual for specific retrace parameters).

Changing retrace buffer parameters may affect memory allocation. Record original values before modification.

If using conversational programming or macros, ensure the retrace routine is called within the same program block sequence and not across separate program calls or subroutines.

Examine the program blocks immediately surrounding the retrace command for active canned cycles (G73-G89), coordinate rotation (G68), or scaling (G51) that may conflict.

Verify that tool nose radius compensation (G41/G42) or tool length compensation states match between the original path and retrace command. Cancel compensation if necessary before retrace.

Check for active work coordinate system changes (G54-G59) or local coordinate system (G52) between the cutting path and retrace - these must remain consistent.

Test the program by removing the retrace command and programming a manual return path to verify basic program syntax is correct, then troubleshoot retrace-specific issues.

Count the number of motion blocks between the start of the cutting path and the retrace command. If exceeding 100-200 blocks, consider breaking into smaller retrace segments.

Simplify the tool path by reducing unnecessary intermediate points, combining linear moves, or increasing tolerance settings in CAM software if applicable.

Check control memory status through diagnostics screen. Low available memory may prevent retrace buffer allocation even for moderate-length paths.

If memory is consistently low, investigate other programs or background processes consuming control resources.

As an alternative, replace the retrace command with an explicitly programmed return path using G00/G01 rapid and feed moves to achieve the same result without buffer dependency.