diff --git a/browser/components/loop/LoopContacts.jsm b/browser/components/loop/LoopContacts.jsm
index 2b58fe2b2cfa..58d0c026dd59 100644
--- a/browser/components/loop/LoopContacts.jsm
+++ b/browser/components/loop/LoopContacts.jsm
@@ -489,6 +489,9 @@ let LoopContactsInternal = Object.freeze({
    *                            finished. The first argument passed will be an
    *                            `Error` object or `null`. The second argument will
    *                            be the contact object, if successful.
+   *                            If no object matching guid could be found,
+   *                            then the callback is called with both arguments
+   *                            set to `null`.
    */
   get: function(guid, callback) {
     LoopStorage.getStore(kObjectStoreName, (err, store) => {
@@ -507,8 +510,7 @@ let LoopContactsInternal = Object.freeze({
 
       request.onsuccess = event => {
         if (!event.target.result) {
-          callback(new Error("Contact with " + kKeyPath + " '" +
-                             guid + "' could not be found"));;
+          callback(null, null);
           return;
         }
         let contact = extend({}, event.target.result);
@@ -528,6 +530,9 @@ let LoopContactsInternal = Object.freeze({
    *                             finished. The first argument passed will be an
    *                             `Error` object or `null`. The second argument will
    *                             be the contact object, if successfull.
+   *                             If no object matching serviceId could be found,
+   *                             then the callback is called with both arguments
+   *                             set to `null`.
    */
   getByServiceId: function(serviceId, callback) {
     LoopStorage.getStore(kObjectStoreName, (err, store) => {
@@ -547,8 +552,7 @@ let LoopContactsInternal = Object.freeze({
 
       request.onsuccess = event => {
         if (!event.target.result) {
-          callback(new Error("Contact with " + kServiceIdIndex + " '" +
-                             serviceId + "' could not be found"));
+          callback(null, null);
           return;
         }
 
@@ -658,6 +662,11 @@ let LoopContactsInternal = Object.freeze({
         return;
       }
 
+      if (!contact) {
+        callback(new Error("Contact with " + kKeyPath + " '" +
+                           guid + "' could not be found"));
+      }
+
       LoopStorage.getStore(kObjectStoreName, (err, store) => {
         if (err) {
           callback(err);
@@ -702,6 +711,11 @@ let LoopContactsInternal = Object.freeze({
         return;
       }
 
+      if (!contact) {
+        callback(new Error("Contact with " + kKeyPath + " '" +
+                           guid + "' could not be found"));
+      }
+
       contact.blocked = true;
       this.update(contact, callback);
     });
@@ -723,6 +737,11 @@ let LoopContactsInternal = Object.freeze({
         return;
       }
 
+      if (!contact) {
+        callback(new Error("Contact with " + kKeyPath + " '" +
+                           guid + "' could not be found"));
+      }
+
       contact.blocked = false;
       this.update(contact, callback);
     });
diff --git a/browser/components/loop/test/mochitest/browser_LoopContacts.js b/browser/components/loop/test/mochitest/browser_LoopContacts.js
index b1dec7529bb8..db32dfb98a73 100644
--- a/browser/components/loop/test/mochitest/browser_LoopContacts.js
+++ b/browser/components/loop/test/mochitest/browser_LoopContacts.js
@@ -230,10 +230,9 @@ add_task(function* () {
 
   // Get a non-existent contact.
   deferred = Promise.defer();
-  LoopContacts.get(1000, err => {
-    Assert.ok(err, "There should be an error");
-    Assert.equal(err.message, "Contact with _guid '1000' could not be found",
-                 "Error message should be correct");
+  LoopContacts.get(1000, (err, contact) => {
+    Assert.ok(!err, "There shouldn't be an error");
+    Assert.ok(!contact, "There shouldn't be a contact");
     deferred.resolve();
   });
   yield deferred.promise;
@@ -250,10 +249,9 @@ add_task(function* () {
   LoopContacts.remove(toRemove, err => {
     Assert.ok(!err, "There shouldn't be an error");
 
-    LoopContacts.get(toRemove, err => {
-      Assert.ok(err, "There should be an error");
-      Assert.equal(err.message, "Contact with _guid '" + toRemove + "' could not be found",
-                   "Error message should be correct");
+    LoopContacts.get(toRemove, (err, contact) => {
+      Assert.ok(!err, "There shouldn't be an error");
+      Assert.ok(!contact, "There shouldn't be a contact");
       deferred.resolve();
     });
   });
@@ -261,10 +259,9 @@ add_task(function* () {
 
   // Remove a non-existing contact.
   deferred = Promise.defer();
-  LoopContacts.remove(1000, err => {
-    Assert.ok(err, "There should be an error");
-    Assert.equal(err.message, "Contact with _guid '1000' could not be found",
-                 "Error message should be correct");
+  LoopContacts.remove(1000, (err, contact) => {
+    Assert.ok(!err, "There shouldn't be an error");
+    Assert.ok(!contact, "There shouldn't be a contact");
     deferred.resolve();
   });
   yield deferred.promise;
@@ -323,7 +320,7 @@ add_task(function* () {
     _guid: 1000,
     bday: newBday
   };
-  LoopContacts.update(toUpdate, err => {
+  LoopContacts.update(toUpdate, (err, contact) => {
     Assert.ok(err, "There should be an error");
     Assert.equal(err.message, "Contact with _guid '1000' could not be found",
                  "Error message should be correct");