diff --git a/file/src/main/java/com/baiyue/file/service/LocalQualificationStorage.java b/file/src/main/java/com/baiyue/file/service/LocalQualificationStorage.java
index 72185c614..ef6371296 100644
--- a/file/src/main/java/com/baiyue/file/service/LocalQualificationStorage.java
+++ b/file/src/main/java/com/baiyue/file/service/LocalQualificationStorage.java
@@ -27,31 +27,25 @@ public class LocalQualificationStorage {
     private static final long MAX_SIZE = 5L * 1024 * 1024;
     private static final Set<String> TYPES = Set.of("image/jpeg", "image/png");
     private final Path root;
+    private final Path qualificationRoot;
 
     public LocalQualificationStorage(@Value("${baiyue.file.storage-root}") String root) {
         this.root = Path.of(root).toAbsolutePath().normalize();
+        this.qualificationRoot = this.root.resolve("qualifications").normalize();
     }
 
     /** 服务启动时校验存储根目录，避免健康检查正常但首次上传才暴露挂载或权限问题。 */
     @PostConstruct
     public void initialize() {
-        Path probe = null;
         try {
             Files.createDirectories(root);
-            if (!Files.isDirectory(root) || !Files.isWritable(root)) {
+            Files.createDirectories(qualificationRoot);
+            if (!qualificationRoot.startsWith(root)
+                    || !Files.isDirectory(qualificationRoot) || !Files.isWritable(qualificationRoot)) {
                 throw new IOException("存储根目录不可写");
             }
-            probe = root.resolve(".qualification-storage-probe-" + UUID.randomUUID());
-            Files.write(probe, new byte[] {0x42}, StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE);
-            Files.delete(probe);
+            verifyWriteAccess();
         } catch (IOException exception) {
-            if (probe != null) {
-                try {
-                    Files.deleteIfExists(probe);
-                } catch (IOException cleanupException) {
-                    exception.addSuppressed(cleanupException);
-                }
-            }
             LOGGER.error("企业资质存储根目录不可用：{}", root, exception);
             throw new IllegalStateException("企业资质存储根目录不可用", exception);
         }
@@ -67,7 +61,7 @@ public class LocalQualificationStorage {
         }
         String extension = "image/png".equals(contentType) ? ".png" : ".jpg";
         String fileName = UUID.randomUUID() + extension;
-        Path directory = root.resolve("qualifications").resolve(Long.toString(tenantId)).normalize();
+        Path directory = tenantDirectory(tenantId);
         Path target = directory.resolve(fileName).normalize();
         if (!target.startsWith(directory)) throw new BizException("Invalid upload path");
         try {
@@ -106,7 +100,7 @@ public class LocalQualificationStorage {
 
     public Resource load(long tenantId, String fileName) {
         if (!fileName.matches("[0-9a-fA-F-]{36}\\.(jpg|png)")) throw new BizException("Invalid file name");
-        Path directory = root.resolve("qualifications").resolve(Long.toString(tenantId)).normalize();
+        Path directory = tenantDirectory(tenantId);
         Path target = directory.resolve(fileName).normalize();
         if (!target.startsWith(directory) || !Files.isRegularFile(target)) throw new BizException("File not found");
         try { return new UrlResource(target.toUri()); }
@@ -117,5 +111,26 @@ public class LocalQualificationStorage {
         try { Files.deleteIfExists(file.path()); } catch (IOException ignored) { }
     }
 
+    private Path tenantDirectory(long tenantId) {
+        Path directory = qualificationRoot.resolve(Long.toString(tenantId)).normalize();
+        if (!directory.startsWith(qualificationRoot)) {
+            throw new BizException("Invalid upload path");
+        }
+        return directory;
+    }
+
+    /** 验证实际挂载目录可创建和删除文件，避免仅凭 isWritable 掩盖 Docker bind mount 权限或只读问题。 */
+    private void verifyWriteAccess() throws IOException {
+        Path probe = Files.createTempFile(qualificationRoot, ".file-service-probe-", ".tmp");
+        try {
+            Files.delete(probe);
+        } catch (IOException exception) {
+            try { Files.deleteIfExists(probe); } catch (IOException cleanupException) {
+                exception.addSuppressed(cleanupException);
+            }
+            throw exception;
+        }
+    }
+
     public record StoredFile(Path path, String fileName, String documentUrl) { }
 }
diff --git a/file/src/test/java/com/baiyue/file/service/LocalQualificationStorageTest.java b/file/src/test/java/com/baiyue/file/service/LocalQualificationStorageTest.java
index 5a3eb2c4e..522355169 100644
--- a/file/src/test/java/com/baiyue/file/service/LocalQualificationStorageTest.java
+++ b/file/src/test/java/com/baiyue/file/service/LocalQualificationStorageTest.java
@@ -20,6 +20,19 @@ class LocalQualificationStorageTest {
     @TempDir
     Path storageRoot;
 
+    @Test
+    void initializeVerifiesTheActualQualificationMountAndCleansUpItsProbe() throws Exception {
+        var storage = new LocalQualificationStorage(storageRoot.toString());
+
+        storage.initialize();
+
+        Path qualificationRoot = storageRoot.resolve("qualifications");
+        assertTrue(Files.isDirectory(qualificationRoot));
+        try (var files = Files.list(qualificationRoot)) {
+            assertEquals(0, files.count());
+        }
+    }
+
     @Test
     void storeReturnsFileServiceUrlBackedByARealTenantFile() throws Exception {
         var storage = new LocalQualificationStorage(storageRoot.toString());
@@ -60,7 +73,7 @@ class LocalQualificationStorageTest {
     void writeFailureReturnsServiceUnavailableInsteadOfBusinessError() throws Exception {
         var storage = new LocalQualificationStorage(storageRoot.toString());
         storage.initialize();
-        Files.writeString(storageRoot.resolve("qualifications"), "阻止创建租户目录");
+        Files.writeString(storageRoot.resolve("qualifications").resolve("10001"), "阻止创建租户目录");
         byte[] png = {(byte) 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a, 0x01};
         var upload = new MockMultipartFile("file", "license.png", "image/png", png);