diff --git a/app/src/main/java/org/fdroid/fdroid/privileged/install/InstallExtensionDialogActivity.java b/app/src/main/java/org/fdroid/fdroid/privileged/install/InstallExtensionDialogActivity.java
index 26bb0c299..d488a9a56 100644
--- a/app/src/main/java/org/fdroid/fdroid/privileged/install/InstallExtensionDialogActivity.java
+++ b/app/src/main/java/org/fdroid/fdroid/privileged/install/InstallExtensionDialogActivity.java
@@ -206,6 +206,21 @@ public class InstallExtensionDialogActivity extends FragmentActivity {
         // hack to get theme applied (which is not automatically applied due to activity's Theme.NoDisplay
         ContextThemeWrapper theme = new ContextThemeWrapper(this, FDroidApp.getCurThemeResId());
 
+        // not support on Android >= 5.1
+        if (android.os.Build.VERSION.SDK_INT >= 22) {
+            AlertDialog.Builder alertBuilder = new AlertDialog.Builder(theme);
+            alertBuilder.setMessage(R.string.system_install_not_supported);
+            alertBuilder.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
+                @Override
+                public void onClick(DialogInterface dialog, int which) {
+                    InstallExtensionDialogActivity.this.setResult(Activity.RESULT_CANCELED);
+                    InstallExtensionDialogActivity.this.finish();
+                }
+            });
+            alertBuilder.create().show();
+            return;
+        }
+
         AlertDialog.Builder alertBuilder = new AlertDialog.Builder(theme);
         alertBuilder.setTitle(R.string.system_install_question);
         String message = InstallExtension.create(getApplicationContext()).getWarningString();
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 074fd531d..24dac9ce0 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -295,6 +295,7 @@
     <string name="system_install_first_time_message">Looks like you have root access on your device. You can now install F-Droid Privileged Extension, tightly coupled with the Android operating system. This allows F-Droid to install, upgrade and uninstall apps on its own.</string>
     <string name="system_uninstall">Do you want to uninstall F-Droid Privileged Extension?</string>
     <string name="system_uninstall_button">Uninstall</string>
+    <string name="system_install_not_supported">Installation of F-Droid Privileged Extension is currently not supported on Android 5.1 or later.</string>
 
     <string name="swap_nfc_title">Touch to swap</string>
     <string name="swap_nfc_description">If your friend has F-Droid and NFC turned on touch your devices together.</string>