fix #163, remove invalid Favorites items on app startup

app/src/main/kotlin/com/simplemobiletools/filemanager/activities/MainActivity.kt

@@ -52,10 +52,10 @@ class MainActivity : SimpleActivity() {
 
         if (savedInstanceState == null) {
             tryInitFileManager()
+            checkWhatsNewDialog()
+            checkIfRootAvailable()
+            checkInvalidFavorites()
         }
-
-        checkWhatsNewDialog()
-        checkIfRootAvailable()
     }
 
     override fun onStop() {
@@ -285,6 +285,16 @@ class MainActivity : SimpleActivity() {
         }.start()
     }
 
+    private fun checkInvalidFavorites() {
+        Thread {
+            config.favorites.forEach {
+                if (!it.startsWith(OTG_PATH) && !isPathOnSD(it) && !getDoesFilePathExist(it)) {
+                    config.removeFavorite(it)
+                }
+            }
+        }.start()
+    }
+
     fun pickedPath(path: String) {
         val resultIntent = Intent()
         val uri = getFilePublicUri(File(path), BuildConfig.APPLICATION_ID)