diff --git a/runelite-client/src/main/java/net/runelite/client/plugins/ExternalPf4jPluginManager.java b/runelite-client/src/main/java/net/runelite/client/plugins/ExternalPf4jPluginManager.java
index 3ed2758e3c..b9e23668c9 100644
--- a/runelite-client/src/main/java/net/runelite/client/plugins/ExternalPf4jPluginManager.java
+++ b/runelite-client/src/main/java/net/runelite/client/plugins/ExternalPf4jPluginManager.java
@@ -6,8 +6,12 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
+import javax.swing.JOptionPane;
+import javax.swing.SwingUtilities;
 import lombok.extern.slf4j.Slf4j;
 import net.runelite.client.RuneLite;
 import net.runelite.client.RuneLiteProperties;
@@ -132,6 +136,7 @@ class ExternalPf4jPluginManager extends DefaultPluginManager
 
 		log.debug("Found {} possible plugins: {}", pluginPaths.size(), pluginPaths);
 
+		Set<String> duplicatePlugins = new HashSet<>();
 		for (Path pluginPath : pluginPaths)
 		{
 			try
@@ -146,11 +151,26 @@ class ExternalPf4jPluginManager extends DefaultPluginManager
 			{
 				if (!(e instanceof PluginAlreadyLoadedException))
 				{
+					String plugin = pluginPath.toString().substring(pluginsRoot.toString().length() + 1);
+					duplicatePlugins.add(plugin);
 					log.error("Could not load plugin {}", pluginPath, e);
 				}
 			}
 		}
 
+		if (!duplicatePlugins.isEmpty())
+		{
+			log.error("Duplicate plugins detected: {}", String.join(", ", duplicatePlugins));
+
+			String formatted = String.join("\n", duplicatePlugins);
+
+			SwingUtilities.invokeLater(() -> JOptionPane.showMessageDialog(null, "You have duplicate plugins in your externalmanager.\n" +
+				"Having duplicate plugins will result in an unstable\n" +
+				"experience, It is highly recommended to delete any\n" +
+				"duplicates, here is a list of the plugins.\n\n" +
+				formatted, "Duplicate Plugins Detected", JOptionPane.WARNING_MESSAGE));
+		}
+
 		try
 		{
 			resolvePlugins();