diff --git a/Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/FillOutStructureCmd.java b/Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/FillOutStructureCmd.java
index f696c755d7..63a724ffee 100644
--- a/Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/FillOutStructureCmd.java
+++ b/Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/FillOutStructureCmd.java
@@ -559,12 +559,16 @@ public class FillOutStructureCmd extends BackgroundCommand {
 		return currentProgram.getDataTypeManager().getUniqueName(new CategoryPath(category), base);
 	}
 
-	private boolean sanityCheck(long offset) {
+	private boolean sanityCheck(long offset, long existingSize) {
+
 		if (offset < 0) {
 			return false; // offsets shouldn't be negative
 		}
+		if (offset < existingSize) {
+			return true; // we have room in the structure
+		}
 		if (offset > 0x1000) {
-			return false; // Arbitrary size cut-off to prevent creating huge structures
+			return false; // bigger than existing size; arbitrary cut-off to prevent huge structures
 		}
 		return true;
 	}
@@ -648,7 +652,7 @@ public class FillOutStructureCmd extends BackgroundCommand {
 						long value = getSigned(inputs[1]);
 						newOff = currentRef.offset +
 							((pcodeOp.getOpcode() == PcodeOp.INT_ADD) ? value : (-value));
-						if (sanityCheck(newOff)) { // should this offset create a location in the structure?
+						if (sanityCheck(newOff, componentMap.getSize())) { // should this offset create a location in the structure?
 							putOnList(output, newOff, todoList, doneList);
 							// Don't do componentMap.addDataType() as data-type info here is likely uninformed
 							componentMap.setMinimumSize(newOff);
@@ -659,7 +663,7 @@ public class FillOutStructureCmd extends BackgroundCommand {
 							break;
 						}
 						newOff = currentRef.offset + getSigned(inputs[1]) * inputs[2].getOffset();
-						if (sanityCheck(newOff)) { // should this offset create a location in the structure?
+						if (sanityCheck(newOff, componentMap.getSize())) { // should this offset create a location in the structure?
 							putOnList(output, newOff, todoList, doneList);
 							// Don't do componentMap.addReference() as data-type info here is likely uninformed
 							componentMap.setMinimumSize(newOff);
@@ -670,7 +674,7 @@ public class FillOutStructureCmd extends BackgroundCommand {
 							break;
 						}
 						long subOff = currentRef.offset + getSigned(inputs[1]);
-						if (sanityCheck(subOff)) { // should this offset create a location in the structure?
+						if (sanityCheck(subOff, componentMap.getSize())) { // should this offset create a location in the structure?
 							putOnList(output, subOff, todoList, doneList);
 							// Don't do componentMap.addReference() as data-type info here is likely uninformed
 							componentMap.setMinimumSize(subOff);