diff --git a/code/core/src/phone/java/com/adobe/marketing/mobile/MobileCore.java b/code/core/src/phone/java/com/adobe/marketing/mobile/MobileCore.java
index 4efd0925..8b44c683 100644
--- a/code/core/src/phone/java/com/adobe/marketing/mobile/MobileCore.java
+++ b/code/core/src/phone/java/com/adobe/marketing/mobile/MobileCore.java
@@ -56,11 +56,13 @@ public static void initialize(
             @Nullable final AdobeCallback<?> completionCallback) {
         if (application == null) {
             Log.error(CoreConstants.LOG_TAG, LOG_TAG, "initialize failed - application is null.");
+            completionCallback.call(null);
             return;
         }
 
         if (initOptions == null) {
             Log.error(CoreConstants.LOG_TAG, LOG_TAG, "initialize failed - initOptions is null.");
+            completionCallback.call(null);
             return;
         }
 
diff --git a/code/core/src/phone/java/com/adobe/marketing/mobile/MobileCoreInitializer.kt b/code/core/src/phone/java/com/adobe/marketing/mobile/MobileCoreInitializer.kt
index 0b903ea9..443a8d7e 100644
--- a/code/core/src/phone/java/com/adobe/marketing/mobile/MobileCoreInitializer.kt
+++ b/code/core/src/phone/java/com/adobe/marketing/mobile/MobileCoreInitializer.kt
@@ -90,6 +90,7 @@ internal class MobileCoreInitializer(
         completionCallback: AdobeCallback<*>?
     ) {
         if (initializeCalled.getAndSet(true)) {
+            completionCallback?.call(null)
             Log.debug(CoreConstants.LOG_TAG, LOG_TAG, "initialize failed - ignoring as it was already called.")
             return
         }
@@ -186,6 +187,7 @@ internal class MobileCoreInitializer(
                 LOG_TAG,
                 "Failed to registerExtensions - setApplication not called"
             )
+            completionCallback?.call(null)
             return
         }