diff --git a/core/pkg/fixhandler/fixhandler.go b/core/pkg/fixhandler/fixhandler.go
index d0e8d3ff..578a1812 100644
--- a/core/pkg/fixhandler/fixhandler.go
+++ b/core/pkg/fixhandler/fixhandler.go
@@ -243,6 +243,7 @@ func (h *FixHandler) getFilePathAndIndex(filePathWithIndex string) (filePath str
 }
 
 func ApplyFixToContent(ctx context.Context, yamlAsString, yamlExpression string) (fixedString string, err error) {
+	yamlAsString = sanitizeYaml(yamlAsString)
 	newline := determineNewlineSeparator(yamlAsString)
 
 	yamlLines := strings.Split(yamlAsString, newline)
@@ -264,6 +265,7 @@ func ApplyFixToContent(ctx context.Context, yamlAsString, yamlExpression string)
 	fixedYamlLines := getFixedYamlLines(yamlLines, fixInfo, newline)
 
 	fixedString = getStringFromSlice(fixedYamlLines, newline)
+	fixedString = revertSanitizeYaml(fixedString)
 
 	return fixedString, nil
 }
@@ -368,3 +370,28 @@ func determineNewlineSeparator(contents string) string {
 		return unixNewline
 	}
 }
+
+// sanitizeYaml receives a YAML file as a string, sanitizes it and returns the result
+//
+// Callers should remember to call the corresponding revertSanitizeYaml function.
+//
+// It applies the following sanitization:
+//
+// - Since `yaml/v3` fails to serialize documents starting with a document
+// separator, we comment it out to be compatible.
+func sanitizeYaml(fileAsString string) string {
+	if fileAsString[:3] == "---" {
+		fileAsString = "# " + fileAsString
+	}
+	return fileAsString
+}
+
+// revertSanitizeYaml receives a sanitized YAML file as a string and reverts the applied sanitization
+//
+// For sanitization details, refer to the sanitizeYaml() function.
+func revertSanitizeYaml(fixedYamlString string) string {
+	if fixedYamlString[:5] == "# ---" {
+		fixedYamlString = fixedYamlString[2:]
+	}
+	return fixedYamlString
+}
diff --git a/core/pkg/fixhandler/fixhandler_test.go b/core/pkg/fixhandler/fixhandler_test.go
index 81d049f1..d598dd83 100644
--- a/core/pkg/fixhandler/fixhandler_test.go
+++ b/core/pkg/fixhandler/fixhandler_test.go
@@ -101,6 +101,13 @@ func getTestCases() []indentationTestCase {
 			"inserts/tc-11-01-expected.yaml",
 		},
 
+		// Starts with ---
+		{
+			"inserts/tc-12-00-begin-with-document-separator.yaml",
+			"select(di==0).spec.containers[0].securityContext.allowPrivilegeEscalation |= false",
+			"inserts/tc-12-01-expected.yaml",
+		},
+
 		// Removal Scenarios
 		{
 			"removals/tc-01-00-input.yaml",
@@ -118,10 +125,10 @@ func getTestCases() []indentationTestCase {
 			"removals/tc-03-01-expected.yaml",
 		},
 		{
-			"removes/tc-04-00-input.yaml",
+			"removals/tc-04-00-input.yaml",
 			`del(select(di==0).spec.containers[0].securityContext) |
 			 del(select(di==1).spec.containers[1])`,
-			"removes/tc-04-01-expected.yaml",
+			"removals/tc-04-01-expected.yaml",
 		},
 
 		// Replace Scenarios
@@ -162,6 +169,12 @@ func getTestCases() []indentationTestCase {
 			 select(di==0).spec.securityContext.runAsRoot |= false`,
 			"hybrids/tc-04-01-expected.yaml",
 		},
+		{
+			"hybrids/tc-05-00-input-leading-doc-separator.yaml",
+			`del(select(di==0).spec.containers[0].securityContext) |
+			 select(di==0).spec.securityContext.runAsRoot |= false`,
+			"hybrids/tc-05-01-expected.yaml",
+		},
 	}
 
 	return indentationTestCases
@@ -169,20 +182,28 @@ func getTestCases() []indentationTestCase {
 
 func TestApplyFixKeepsFormatting(t *testing.T) {
 	testCases := getTestCases()
+	getTestDataPath := func(filename string) string {
+		currentFile := "testdata/" + filename
+		return filepath.Join(testutils.CurrentDir(), currentFile)
+	}
 
 	for _, tc := range testCases {
 		t.Run(tc.inputFile, func(t *testing.T) {
-			getTestDataPath := func(filename string) string {
-				currentFile := "testdata/" + filename
-				return filepath.Join(testutils.CurrentDir(), currentFile)
+			inputFilename := getTestDataPath(tc.inputFile)
+			input, err := os.ReadFile(inputFilename)
+			if err != nil {
+				t.Fatalf(`Unable to open file %s due to: %v`, inputFilename, err)
+			}
+			expectedFilename := getTestDataPath(tc.expectedFile)
+			wantRaw, err := os.ReadFile(expectedFilename)
+			if err != nil {
+				t.Fatalf(`Unable to open file %s due to: %v`, expectedFilename, err)
 			}
-
-			input, _ := os.ReadFile(getTestDataPath(tc.inputFile))
-			wantRaw, _ := os.ReadFile(getTestDataPath(tc.expectedFile))
 			want := string(wantRaw)
 			expression := tc.yamlExpression
 
-			got, _ := ApplyFixToContent(context.TODO(), string(input), expression)
+			fileAsString := string(input)
+			got, _ := ApplyFixToContent(context.TODO(), fileAsString, expression)
 
 			assert.Equalf(
 				t, want, got,
diff --git a/core/pkg/fixhandler/testdata/hybrids/tc-05-00-input-leading-doc-separator.yaml b/core/pkg/fixhandler/testdata/hybrids/tc-05-00-input-leading-doc-separator.yaml
new file mode 100644
index 00000000..9a6bc1bf
--- /dev/null
+++ b/core/pkg/fixhandler/testdata/hybrids/tc-05-00-input-leading-doc-separator.yaml
@@ -0,0 +1,22 @@
+# Fix to Apply:
+# REMOVE:
+# "del(select(di==0).spec.containers[0].securityContext)"
+
+# INSERT:
+# select(di==0).spec.securityContext.runAsRoot: false
+
+
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: insert_to_mapping_node_1
+
+spec:
+  containers:
+    - name: nginx_container
+
+      image: nginx
+
+      securityContext:
+        runAsRoot: true
diff --git a/core/pkg/fixhandler/testdata/hybrids/tc-05-01-expected.yaml b/core/pkg/fixhandler/testdata/hybrids/tc-05-01-expected.yaml
new file mode 100644
index 00000000..5beb28d4
--- /dev/null
+++ b/core/pkg/fixhandler/testdata/hybrids/tc-05-01-expected.yaml
@@ -0,0 +1,22 @@
+# Fix to Apply:
+# REMOVE:
+# "del(select(di==0).spec.containers[0].securityContext)"
+
+# INSERT:
+# select(di==0).spec.securityContext.runAsRoot: false
+
+
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: insert_to_mapping_node_1
+
+spec:
+  containers:
+    - name: nginx_container
+
+      image: nginx
+  securityContext:
+    runAsRoot: false
+
diff --git a/core/pkg/fixhandler/testdata/inserts/tc-12-00-begin-with-document-separator.yaml b/core/pkg/fixhandler/testdata/inserts/tc-12-00-begin-with-document-separator.yaml
new file mode 100644
index 00000000..61d8bee3
--- /dev/null
+++ b/core/pkg/fixhandler/testdata/inserts/tc-12-00-begin-with-document-separator.yaml
@@ -0,0 +1,10 @@
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: begin-with-document-separator
+
+spec:
+  containers:
+  - name: nginx_container
+    image: nginx
diff --git a/core/pkg/fixhandler/testdata/inserts/tc-12-01-expected.yaml b/core/pkg/fixhandler/testdata/inserts/tc-12-01-expected.yaml
new file mode 100644
index 00000000..8116502f
--- /dev/null
+++ b/core/pkg/fixhandler/testdata/inserts/tc-12-01-expected.yaml
@@ -0,0 +1,12 @@
+---
+apiVersion: v1
+kind: Pod
+metadata:
+  name: begin-with-document-separator
+
+spec:
+  containers:
+  - name: nginx_container
+    image: nginx
+    securityContext:
+      allowPrivilegeEscalation: false