diff --git a/spellchecker/hunspell/src/test/java/org/omegat/spellchecker/hunspell/HunspellSpellcheckerTest.java b/spellchecker/hunspell/src/test/java/org/omegat/spellchecker/hunspell/HunspellSpellcheckerTest.java
index 2c6e8873d7..ee4471a263 100644
--- a/spellchecker/hunspell/src/test/java/org/omegat/spellchecker/hunspell/HunspellSpellcheckerTest.java
+++ b/spellchecker/hunspell/src/test/java/org/omegat/spellchecker/hunspell/HunspellSpellcheckerTest.java
@@ -32,6 +32,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Collections;
+import java.util.concurrent.CountDownLatch;
 
 import org.apache.commons.io.FileUtils;
 import org.junit.AfterClass;
@@ -42,11 +43,13 @@
 
 import org.omegat.core.Core;
 import org.omegat.core.CoreEvents;
+import org.omegat.core.TestCoreInitializer;
 import org.omegat.core.data.NotLoadedProject;
 import org.omegat.core.data.ProjectProperties;
 import org.omegat.core.events.IProjectEventListener;
 import org.omegat.core.spellchecker.ISpellChecker;
 import org.omegat.filters2.master.PluginUtils;
+import org.omegat.gui.main.ConsoleWindow;
 import org.omegat.util.Language;
 import org.omegat.util.TestPreferencesInitializer;
 
@@ -58,12 +61,13 @@ public class HunspellSpellcheckerTest {
     private static Path configDir;
 
     @BeforeClass
-    public static void setUpClass() throws IOException {
+    public static void setUpClass() throws Exception {
         PluginUtils.loadPlugins(Collections.emptyMap());
         tmpDir = Files.createTempDirectory("omegat");
         assertThat(tmpDir.toFile()).isDirectory();
         configDir = Files.createDirectory(tmpDir.resolve(".omegat"));
         TestPreferencesInitializer.init(configDir.toString());
+        TestCoreInitializer.initMainWindow(new ConsoleWindow());
         Files.createDirectory(configDir.resolve("spelling"));
         copyFile("es_MX.aff");
         copyFile("es_MX.dic");
@@ -138,9 +142,15 @@ public ProjectProperties getProjectProperties() {
         });
         HunSpellCheckerMock checker = new HunSpellCheckerMock();
         assertThat(checker.initialize()).as("Success initialize").isTrue();
+        assertThat(checker.getInitializeCounter()).as("Hunspell Checker initialized once").isEqualTo(1);
+        // Fire project change events twice
+        final CountDownLatch latch = new CountDownLatch(2);
+        CoreEvents.registerProjectChangeListener(eventType -> latch.countDown());
         CoreEvents.fireProjectChange(IProjectEventListener.PROJECT_CHANGE_TYPE.LOAD);
         CoreEvents.fireProjectChange(IProjectEventListener.PROJECT_CHANGE_TYPE.LOAD);
-        assertThat(checker.getCounter()).as("Hunspell Checker initialized once").isEqualTo(1);
+        latch.await();
+        //
+        assertThat(checker.getInitializeCounter()).as("Hunspell Checker loaded 3rd times").isEqualTo(3);
     }
 
     private static void copyFile(String target) throws IOException {
@@ -154,19 +164,19 @@ private static void copyFile(String target) throws IOException {
     }
 
     public static class HunSpellCheckerMock extends HunSpellChecker {
-        private int counter = 0;
+        private int initializeCounter = 0;
         public HunSpellCheckerMock() {
             super();
         }
 
         @Override
         public boolean initialize() {
-            counter++;
+            initializeCounter++;
             return super.initialize();
         }
 
-        public int getCounter() {
-            return counter;
+        public int getInitializeCounter() {
+            return initializeCounter;
         }
     }
 }
diff --git a/src/org/omegat/externalfinder/ExternalFinder.java b/src/org/omegat/externalfinder/ExternalFinder.java
index fcf0823a7d..61a18ad65b 100644
--- a/src/org/omegat/externalfinder/ExternalFinder.java
+++ b/src/org/omegat/externalfinder/ExternalFinder.java
@@ -58,6 +58,7 @@
 import org.omegat.util.StaticUtils;
 import org.omegat.util.gui.MenuExtender;
 import org.omegat.util.gui.MenuItemPager;
+import org.omegat.util.gui.StaticUIUtils;
 
 /**
  * Entry point for ExternalFinder functionality.
@@ -89,9 +90,11 @@ private ExternalFinder() {
      * OmegaT will call this method when loading.
      */
     public static void loadPlugins() {
-        // register listeners
-        CoreEvents.registerApplicationEventListener(generateIApplicationEventListener());
-        CoreEvents.registerProjectChangeListener(generateIProjectEventListener());
+        // register listeners when GUI environment
+        if (StaticUIUtils.isGUI()) {
+            CoreEvents.registerApplicationEventListener(generateIApplicationEventListener());
+            CoreEvents.registerProjectChangeListener(generateIProjectEventListener());
+        }
     }
 
     private static IProjectEventListener generateIProjectEventListener() {