diff --git a/assets/testdata/.env.initium.empty b/assets/testdata/.env.initium.empty
new file mode 100644
index 00000000..e69de29b
diff --git a/assets/testdata/.env.secretref.invalid1 b/assets/testdata/.env.secretref.initium.invalid1
similarity index 100%
rename from assets/testdata/.env.secretref.invalid1
rename to assets/testdata/.env.secretref.initium.invalid1
diff --git a/assets/testdata/.env.secretref.invalid3 b/assets/testdata/.env.secretref.initium.invalid2
similarity index 100%
rename from assets/testdata/.env.secretref.invalid3
rename to assets/testdata/.env.secretref.initium.invalid2
diff --git a/assets/testdata/.env.secretref.invalid2 b/assets/testdata/.env.secretref.invalid2
deleted file mode 100644
index 3e56365c..00000000
--- a/assets/testdata/.env.secretref.invalid2
+++ /dev/null
@@ -1,2 +0,0 @@
-# Wrong format
-MOCK5=kubernetessecretname/kubernetesecretkey
diff --git a/src/services/k8s/knative.go b/src/services/k8s/knative.go
index b736880a..03c3f222 100644
--- a/src/services/k8s/knative.go
+++ b/src/services/k8s/knative.go
@@ -3,7 +3,9 @@ package k8s
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
+	"os"
 	"path"
 	"strings"
 	"text/template"
@@ -143,22 +145,10 @@ func setSecretEnv(manifest *servingv1.Service, SecretRefEnvFile string, manifest
 }
 
 func validateSecretEnvVar(secretEnvVar corev1.EnvVar) error {
-	invalidChars := []string{
-		"\"",
-		"'",
-	}
-
 	// Mandatory char
 	if !strings.Contains(secretEnvVar.Value, "/") {
 		return fmt.Errorf("Invalid secret format for '%s'. Missing '/' char. Value must be in the format <secret-name>/<secret-key>, instead of '%s'", secretEnvVar.Name, secretEnvVar.Value)
 	}
-
-	// Invalid chars
-	for _, value := range invalidChars {
-		if strings.Contains(secretEnvVar.Value, value) {
-			return fmt.Errorf("Invalid secret format for '%s'. Invalid char found (\", ')", secretEnvVar.Name)
-		}
-	}
 	return nil
 }
 
@@ -173,13 +163,18 @@ func setEnv(manifest *servingv1.Service, envFile string, manifestEnvVars map[str
 
 func loadEnvFile(envFile string, manifestEnvVars map[string]string) ([]corev1.EnvVar, error) {
 	var envVarList []corev1.EnvVar
+	
+	if _, err := os.Stat(envFile); errors.Is(err, os.ErrNotExist) {
+		return nil, nil
+	}
+	
 	envVariables, err := godotenv.Read(envFile)
 	if err != nil {
 		return nil, fmt.Errorf("Error loading .env file. '%s' already set", err)
 	}
 
 	if len(envVariables) > 0 {
-		for key, value := range envVariables {			
+		for key, value := range envVariables {
 			if manifestEnvVars[key] == "" {
 				manifestEnvVars[key] = value
 				envVar := corev1.EnvVar{
diff --git a/src/services/k8s/knative_test.go b/src/services/k8s/knative_test.go
index 014b9827..bb4c94f4 100644
--- a/src/services/k8s/knative_test.go
+++ b/src/services/k8s/knative_test.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"strings"
 	"testing"
 
 	"gotest.tools/v3/assert"
@@ -118,16 +119,6 @@ func TestLoadManifestForPrivateService(t *testing.T) {
 	assert.Assert(t, labels[visibilityLabel] == visibilityLabelPrivateValue)
 }
 
-// TODO: New use cases:
-// 1 -> All happy and working
-// 2 -> Invalid chars
-// 3 -> Mandatory '/' char
-// 4 -> Conflicting env vars between files
-// 5 -> Invalid dotenv format
-// 6 -> Empty files
-// 7 -> only .env is empty
-// 8 -> only .env.secretref is empty
-
 func TestLoadManifestEnvironmentVariables(t *testing.T) {
 	envVariablesFromFile, err := godotenv.Read(envTestFile)
 	if err != nil {
@@ -150,3 +141,37 @@ func TestLoadManifestEnvironmentVariables(t *testing.T) {
 	assert.Assert(t, len(envVariablesFromFile) == 0, "Missing environment variables: %s", envVariablesFromFile )
 	assert.Assert(t, len(secretRefEnvVariablesFromFile) == 0, "Missing secret environment variables: %s", secretRefEnvVariablesFromFile)
 }
+
+func TestLoadManifestEnvironmentVariablesInvalidFormat(t *testing.T) {
+	invalidEnvTestFile := path.Join(root, "assets/testdata/.env.initium.invalid")
+	serviceManifest, err := LoadManifest(namespace, commitSha, proj, dockerImage, invalidEnvTestFile, secretRefEnvTestFile)
+	assert.Assert(t, err != nil && strings.Contains(err.Error(), "Error loading .env file"), "There should be a validation error when missing a mandatory character" )
+	assert.Assert(t, serviceManifest == nil, "Expected nil manifest, got %v", serviceManifest)
+}
+
+func TestLoadManifestSecretRefEnvironmentMandatoryChars(t *testing.T) {
+	invalidSecretRefEnvTestFile := path.Join(root, "assets/testdata/.env.secretref.initium.invalid2")
+	serviceManifest, err := LoadManifest(namespace, commitSha, proj, dockerImage, envTestFile, invalidSecretRefEnvTestFile)
+	assert.Assert(t, err != nil && strings.Contains(err.Error(), "Value must be in the format <secret-name>/<secret-key>"), "There should be a validation error when missing a mandatory character" )
+	assert.Assert(t, serviceManifest == nil, "Expected nil manifest, got %v", serviceManifest)
+}
+
+func TestLoadManifestSecretRefEnvironmentConflict(t *testing.T) {
+	invalidSecretRefEnvTestFile := path.Join(root, "assets/testdata/.env.secretref.conflictingvar")
+	serviceManifest, err := LoadManifest(namespace, commitSha, proj, dockerImage, envTestFile, invalidSecretRefEnvTestFile)
+	assert.Assert(t, err != nil && strings.Contains(err.Error(), "Conflicting environment variable"), "There should be a validation error when missing a mandatory character" )
+	assert.Assert(t, serviceManifest == nil, "Expected nil manifest, got %v", serviceManifest)
+}
+
+func TestLoadManifestSecretEnvironmentVariablesFileDoesNotExist(t *testing.T) {
+	nonExistingEnvTestFile := "idontexist"
+	nonExistingSecretRefEnvTestFile := "idontexist"
+	serviceManifest, err := LoadManifest(namespace, commitSha, proj, dockerImage, nonExistingEnvTestFile, nonExistingSecretRefEnvTestFile)
+	assert.Assert(t, serviceManifest != nil, "Expected maifest to be created without issues. Dotenv files are optional. Err: %s", err)
+}
+
+func TestLoadManifestSecretEnvironmentVariablesEmptyFile(t *testing.T) {
+	emtpyFile := path.Join(root, "assets/testdata/.env.initium.empty")
+	serviceManifest, err := LoadManifest(namespace, commitSha, proj, dockerImage, emtpyFile, emtpyFile)
+	assert.Assert(t, serviceManifest != nil, "Expected maifest to be created without issues. Dotenv files are optional. Err: %s", err)
+}