diff --git a/src/client/web/src/components/__test__/panel_sharings.test.tsx b/src/client/web/src/components/__test__/panel_sharings.test.tsx
index 3457936..b147a5c 100644
--- a/src/client/web/src/components/__test__/panel_sharings.test.tsx
+++ b/src/client/web/src/components/__test__/panel_sharings.test.tsx
@@ -39,33 +39,6 @@ describe("SharingsPanel", () => {
     };
   };
 
-  test("add sharing", async () => {
-    const { sharingsPanel, usersCl, filesCl } = initSharingsPanel();
-
-    const newSharings = [
-      "mock_sharingfolder1",
-      "mock_sharingfolder2",
-      "newSharing",
-    ];
-
-    filesCl.setMock({
-      ...filesResps,
-      listSharingsMockResp: {
-        status: 200,
-        statusText: "",
-        data: {
-          sharingDirs: newSharings,
-        },
-      },
-    });
-
-    await sharingsPanel.addSharing();
-
-    // TODO: check addSharing's input
-    expect(updater().props.filesInfo.isSharing).toEqual(true);
-    expect(updater().props.sharingsInfo.sharings).toEqual(List(newSharings));
-  });
-
   test("delete sharing", async () => {
     const { sharingsPanel, usersCl, filesCl } = initSharingsPanel();
 
diff --git a/src/client/web/src/components/panel_files.tsx b/src/client/web/src/components/panel_files.tsx
index 42610a2..7fa4e74 100644
--- a/src/client/web/src/components/panel_files.tsx
+++ b/src/client/web/src/components/panel_files.tsx
@@ -9,6 +9,7 @@ import { RiFile2Fill } from "@react-icons/all-files/ri/RiFile2Fill";
 import { RiFileList2Fill } from "@react-icons/all-files/ri/RiFileList2Fill";
 
 import { alertMsg, confirmMsg } from "../common/env";
+import { getErrMsg } from "../common/utils";
 import { updater } from "./state_updater";
 import { ICoreState, MsgProps, UIProps } from "./core_state";
 import { LoginProps } from "./pane_login";
@@ -129,7 +130,7 @@ export class FilesPanel extends React.Component<Props, State, {}> {
 
     const status = updater().addUploads(fileList);
     if (status !== "") {
-      alertMsg(this.props.msg.pkg.get("upload.add.fail"));
+      alertMsg(getErrMsg(this.props.msg.pkg, "upload.add.fail", status));
     }
     this.props.update(updater().updateUploadingsInfo);
   };
@@ -248,13 +249,13 @@ export class FilesPanel extends React.Component<Props, State, {}> {
 
     return updater()
       .setItems(dirPath)
-      .then(() => {
-        return updater().listSharings();
-      })
       .then(() => {
         return updater().isSharing(dirPath.join("/"));
       })
-      .then(() => {
+      .then((status: string) => {
+        if (status !== "") {
+          alertMsg(getErrMsg(this.props.msg.pkg, "op.fail", status));
+        }
         this.props.update(updater().updateFilesInfo);
         this.props.update(updater().updateSharingsInfo);
       });
@@ -305,15 +306,19 @@ export class FilesPanel extends React.Component<Props, State, {}> {
   addSharing = async () => {
     return updater()
       .addSharing()
-      .then((ok) => {
-        if (!ok) {
-          alertMsg(this.props.msg.pkg.get("browser.share.add.fail"));
+      .then((status: string) => {
+        if (status !== "") {
+          alertMsg(getErrMsg(this.props.msg.pkg, "op.fail", status));
+          return "";
         } else {
           updater().setSharing(true);
           return updater().listSharings();
         }
       })
-      .then(() => {
+      .then((status: string) => {
+        if (status !== "") {
+          alertMsg(getErrMsg(this.props.msg.pkg, "op.fail", status));
+        }
         this.props.update(updater().updateSharingsInfo);
         this.props.update(updater().updateFilesInfo);
       });
@@ -322,15 +327,19 @@ export class FilesPanel extends React.Component<Props, State, {}> {
   deleteSharing = async (dirPath: string) => {
     return updater()
       .deleteSharing(dirPath)
-      .then((ok) => {
-        if (!ok) {
-          alertMsg(this.props.msg.pkg.get("browser.share.del.fail"));
+      .then((status) => {
+        if (status !== "") {
+          alertMsg(getErrMsg(this.props.msg.pkg, "op.fail", status));
+          return "";
         } else {
           updater().setSharing(false);
           return updater().listSharings();
         }
       })
-      .then(() => {
+      .then((status: string) => {
+        if (status !== "") {
+          alertMsg(getErrMsg(this.props.msg.pkg, "op.fail", status));
+        }
         this.props.update(updater().updateSharingsInfo);
         this.props.update(updater().updateFilesInfo);
       });
diff --git a/src/client/web/src/components/panel_sharings.tsx b/src/client/web/src/components/panel_sharings.tsx
index a44fe65..d9db0da 100644
--- a/src/client/web/src/components/panel_sharings.tsx
+++ b/src/client/web/src/components/panel_sharings.tsx
@@ -5,6 +5,7 @@ import { RiShareBoxLine } from "@react-icons/all-files/ri/RiShareBoxLine";
 import { RiFolderSharedFill } from "@react-icons/all-files/ri/RiFolderSharedFill";
 import { RiEmotionSadLine } from "@react-icons/all-files/ri/RiEmotionSadLine";
 
+import { getErrMsg } from "../common/utils";
 import { alertMsg, confirmMsg } from "../common/env";
 import { updater } from "./state_updater";
 import { ICoreState, MsgProps, UIProps } from "./core_state";
@@ -33,48 +34,28 @@ export class SharingsPanel extends React.Component<Props, State, {}> {
     this.state = {};
   }
 
-  addSharing = async () => {
-    return updater()
-      .addSharing()
-      .then((ok) => {
-        if (!ok) {
-          alertMsg(this.props.msg.pkg.get("browser.share.add.fail"));
-        } else {
-          updater().setSharing(true);
-          return this.listSharings();
-        }
-      })
-      .then(() => {
-        this.props.update(updater().updateFilesInfo);
-        this.props.update(updater().updateSharingsInfo);
-      });
-  };
-
   deleteSharing = async (dirPath: string) => {
     return updater()
       .deleteSharing(dirPath)
-      .then((ok) => {
-        if (!ok) {
-          alertMsg(this.props.msg.pkg.get("browser.share.del.fail"));
+      .then((status: string) => {
+        if (status !== "") {
+          alertMsg(getErrMsg(this.props.msg.pkg, "op.fail", status));
         } else {
           updater().setSharing(false);
           return this.listSharings();
         }
-      })
-      .then(() => {
-        this.props.update(updater().updateFilesInfo);
-        this.props.update(updater().updateFilesInfo);
       });
   };
 
   listSharings = async () => {
     return updater()
       .listSharings()
-      .then((ok) => {
-        if (ok) {
-          this.props.update(updater().updateFilesInfo);
-          this.props.update(updater().updateSharingsInfo);
+      .then((status: string) => {
+        if (status !== "") {
+          alertMsg(getErrMsg(this.props.msg.pkg, "op.fail", status));
         }
+        this.props.update(updater().updateFilesInfo);
+        this.props.update(updater().updateSharingsInfo);
       });
   };
 
diff --git a/src/client/web/src/components/panel_uploadings.tsx b/src/client/web/src/components/panel_uploadings.tsx
index 5475498..348fdf4 100644
--- a/src/client/web/src/components/panel_uploadings.tsx
+++ b/src/client/web/src/components/panel_uploadings.tsx
@@ -7,6 +7,7 @@ import { RiUploadCloudLine } from "@react-icons/all-files/ri/RiUploadCloudLine";
 import { RiEmotionSadLine } from "@react-icons/all-files/ri/RiEmotionSadLine";
 
 import { alertMsg } from "../common/env";
+import { getErrMsg } from "../common/utils";
 import { updater } from "./state_updater";
 import { ICoreState, MsgProps, UIProps } from "./core_state";
 import { LoginProps } from "./pane_login";
@@ -41,14 +42,15 @@ export class UploadingsPanel extends React.Component<Props, State, {}> {
       .then((status: string) => {
         if (status !== "") {
           alertMsg(
-            `${this.props.msg.pkg.get(
-              "browser.upload.del.fail"
-            )}: ${this.props.msg.pkg.get(status)}`
+            getErrMsg(this.props.msg.pkg, "browser.upload.del.fail", status)
           );
         }
         return updater().refreshUploadings();
       })
-      .then(() => {
+      .then((status: string) => {
+        if (status !== "") {
+          alertMsg(getErrMsg(this.props.msg.pkg, "op.fail", status));
+        }
         return updater().self();
       })
       .then(() => {
diff --git a/src/client/web/src/components/state_updater.ts b/src/client/web/src/components/state_updater.ts
index 7adea2e..304a1b4 100644
--- a/src/client/web/src/components/state_updater.ts
+++ b/src/client/web/src/components/state_updater.ts
@@ -70,7 +70,7 @@ export class Updater {
         file.name
       );
       const status = Up().add(file, filePath);
-      if (status !== ""){
+      if (status !== "") {
         return status;
       }
     });
@@ -97,44 +97,45 @@ export class Updater {
     );
   };
 
-  addSharing = async (): Promise<boolean> => {
+  addSharing = async (): Promise<string> => {
     const dirPath = this.props.filesInfo.dirPath.join("/");
     const resp = await this.filesClient.addSharing(dirPath);
-    return resp.status === 200;
+    return resp.status === 200 ? "" : "server.fail";
   };
 
-  deleteSharing = async (dirPath: string): Promise<boolean> => {
+  deleteSharing = async (dirPath: string): Promise<string> => {
     const resp = await this.filesClient.deleteSharing(dirPath);
-    return resp.status === 200;
+    return resp.status === 200 ? "" : "server.fail";
   };
 
-  isSharing = async (dirPath: string): Promise<boolean> => {
+  isSharing = async (dirPath: string): Promise<string> => {
     const resp = await this.filesClient.isSharing(dirPath);
+    // TODO: differentiate 404 and error
     this.props.filesInfo.isSharing = resp.status === 200;
-    return resp.status === 200; // TODO: differentiate 404 and error
+    return resp.status === 200 ? "" : "server.fail";
   };
 
   setSharing = (shared: boolean) => {
     this.props.filesInfo.isSharing = shared;
   };
 
-  listSharings = async (): Promise<boolean> => {
+  listSharings = async (): Promise<string> => {
     const resp = await this.filesClient.listSharings();
     this.props.sharingsInfo.sharings =
       resp.status === 200
         ? List<string>(resp.data.sharingDirs)
         : this.props.sharingsInfo.sharings;
-    return resp.status === 200;
+    return resp.status === 200 ? "" : "server.fail";
   };
 
-  refreshUploadings = async (): Promise<boolean> => {
-    // this function get information from server and merge them with local information
-    // because some information (error) can only be detected from local
+  // this function gets information from server and merge them with local information
+  // because some information (error) can only be detected from local
+  refreshUploadings = async (): Promise<string> => {
     const luResp = await this.filesClient.listUploadings();
     if (luResp.status !== 200) {
-      // TODO: i18n
+      // TODO: log error
       console.error(luResp.data);
-      return false;
+      return "server.fail";
     }
 
     let localUploads = Map<string, UploadEntry>([]);
@@ -167,11 +168,11 @@ export class Updater {
     });
 
     this.props.uploadingsInfo.uploadings = updatedUploads;
-    return true;
+    return "";
   };
 
-  stopUploading = (filePath: string) => {
-    Up().stop(filePath);
+  stopUploading = (filePath: string): string => {
+    return Up().stop(filePath);
   };
 
   mkDir = async (dirPath: string): Promise<void> => {
@@ -369,14 +370,14 @@ export class Updater {
     return Promise.all([
       this.getClientCfg(),
       this.syncLan(),
-      this.isSharing(this.props.filesInfo.dirPath.join("/")),
+      this.isSharing(this.props.filesInfo.dirPath.join("/")), // TODO: they return Promise<string>, check its status
     ]);
   };
 
   initStateForAuthedUser = async (): Promise<any> => {
     // TOOD: status is ignored, should return alert
     this.initUploads(); // ignore return because it always succeed
-    return Promise.all([this.refreshUploadings(), this.listSharings()]);
+    return Promise.all([this.refreshUploadings(), this.listSharings()]); // TODO: they return Promise<string>, check its status
   };
 
   initStateForAdmin = async (): Promise<any> => {
diff --git a/src/client/web/src/worker/upload_mgr.ts b/src/client/web/src/worker/upload_mgr.ts
index c4af6db..cbc6de1 100644
--- a/src/client/web/src/worker/upload_mgr.ts
+++ b/src/client/web/src/worker/upload_mgr.ts
@@ -141,7 +141,7 @@ export class UploadMgr {
           state: UploadState.Ready,
         });
       } else {
-        status = "op.fail";
+        status = "uploadMgr.err";
       }
     }
 
@@ -159,7 +159,7 @@ export class UploadMgr {
         state: UploadState.Stopped,
       });
     } else {
-      status = "op.fail";
+      status = "uploadMgr.err";
     }
 
     this.statusCb(this.infos.toMap(), false);