diff --git a/app/ui/legacy/src/main/java/com/fsck/k9/activity/MessageList.kt b/app/ui/legacy/src/main/java/com/fsck/k9/activity/MessageList.kt
index b8ca57ad9a218de858ef49905639ebb2fa2b789c..d82501ae9f4c5e0e106710789a24ed86418d900a 100644
--- a/app/ui/legacy/src/main/java/com/fsck/k9/activity/MessageList.kt
+++ b/app/ui/legacy/src/main/java/com/fsck/k9/activity/MessageList.kt
@@ -120,7 +120,7 @@ open class MessageList :
 
     private val permissionUiHelper: PermissionUiHelper = K9PermissionUiHelper(this)
 
-    private lateinit var actionBar: ActionBar
+    private var actionBar: ActionBar? = null
     private lateinit var searchView: SearchView
     private var drawer: K9Drawer? = null
     private var openFolderTransaction: FragmentTransaction? = null
@@ -587,7 +587,7 @@ open class MessageList :
 
     private fun initializeActionBar() {
         actionBar = supportActionBar!!
-        actionBar.setDisplayHomeAsUpEnabled(true)
+        actionBar?.setDisplayHomeAsUpEnabled(true)
     }
 
     private fun initializeDrawer(savedInstanceState: Bundle?) {
@@ -1250,8 +1250,8 @@ open class MessageList :
     }
 
     fun setActionBarTitle(title: String, subtitle: String? = null) {
-        actionBar.title = title
-        actionBar.subtitle = subtitle
+        actionBar?.title = title
+        actionBar?.subtitle = subtitle
     }
 
     override fun setMessageListTitle(title: String, subtitle: String?) {
@@ -1261,11 +1261,11 @@ open class MessageList :
     }
 
     override fun setMessageListProgressEnabled(enable: Boolean) {
-        progressBar!!.visibility = if (enable) View.VISIBLE else View.INVISIBLE
+        progressBar?.visibility = if (enable) View.VISIBLE else View.INVISIBLE
     }
 
     override fun setMessageListProgress(progress: Int) {
-        progressBar!!.progress = progress
+        progressBar?.progress = progress
     }
 
     override fun openMessage(messageReference: MessageReference) {
@@ -1276,9 +1276,7 @@ open class MessageList :
         if (draftsFolderId != null && folderId == draftsFolderId) {
             MessageActions.actionEditDraft(this, messageReference)
         } else {
-            if (messageListFragment != null) {
-                messageListFragment!!.setActiveMessage(messageReference)
-            }
+            messageListFragment?.setActiveMessage(messageReference)
 
             val fragment = MessageViewFragment.newInstance(messageReference)
             val fragmentTransaction = supportFragmentManager.beginTransaction()
@@ -1600,12 +1598,12 @@ open class MessageList :
 
     private fun lockDrawer() {
         drawer!!.lock()
-        actionBar.setHomeAsUpIndicator(R.drawable.ic_arrow_back)
+        actionBar?.setHomeAsUpIndicator(R.drawable.ic_arrow_back)
     }
 
     private fun unlockDrawer() {
         drawer!!.unlock()
-        actionBar.setHomeAsUpIndicator(getResId(R.attr.iconMenu))
+        actionBar?.setHomeAsUpIndicator(getResId(R.attr.iconMenu))
     }
 
     private fun initializeFromLocalSearch(search: LocalSearch?) {