diff --git a/mateclaw-server/src/main/java/vip/mate/workspace/conversation/ConversationService.java b/mateclaw-server/src/main/java/vip/mate/workspace/conversation/ConversationService.java
index 81c6a927..06128861 100644
--- a/mateclaw-server/src/main/java/vip/mate/workspace/conversation/ConversationService.java
+++ b/mateclaw-server/src/main/java/vip/mate/workspace/conversation/ConversationService.java
@@ -21,6 +21,7 @@ import vip.mate.workspace.conversation.vo.MessageVO;
 
 import java.io.IOException;
 import java.nio.file.Files;
+import java.nio.file.InvalidPathException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.time.LocalDateTime;
@@ -791,7 +792,17 @@ public class ConversationService {
      * 清理会话关联的附件文件
      */
     public void cleanAttachmentFiles(String conversationId) {
-        Path dir = UPLOAD_ROOT.resolve(conversationId);
+        Path dir;
+        try {
+            dir = UPLOAD_ROOT.resolve(conversationId);
+        } catch (InvalidPathException e) {
+            // Conversation id contains characters illegal on this filesystem
+            // (e.g. ':' in cron:<jobId> on Windows). No attachments could
+            // ever have been written under such an id on this OS, so there
+            // is nothing to clean.
+            log.debug("Skipping attachment cleanup for non-path-safe conversation id: {}", conversationId);
+            return;
+        }
         if (!Files.exists(dir)) {
             return;
         }