diff --git a/src/services/dataService.js b/src/services/dataService.js
index abc1a00..ff9ded2 100644
--- a/src/services/dataService.js
+++ b/src/services/dataService.js
@@ -1,6 +1,5 @@
 import { Codex } from "@codex-storage/sdk-js";
 import { NodeUploadStategy } from "@codex-storage/sdk-js/node";
-import mime from "mime-types";
 import path from "path";
 import fs from "fs";
 
@@ -11,19 +10,22 @@ export class DataService {
 
   upload = async (filePath) => {
     const data = this.getCodexData();
+
+    // We can use mime util to determine the content type of the file. But Codex will reject some
+    // mimetypes. So we set it to octet-stream always.
+    const contentType = "application/octet-stream";
+
     const filename = path.basename(filePath);
-    const contentType = mime.lookup(filePath) || "application/octet-stream";
     const fileData = fs.readFileSync(filePath);
 
-    const strategy = new NodeUploadStategy(fileData, {
-      filename: filename,
-      mimetype: contentType,
-    });
+    const metadata = { filename: filename, mimetype: contentType };
+
+    const strategy = new NodeUploadStategy(fileData, metadata); 
     const uploadResponse = data.upload(strategy);
     const res = await uploadResponse.result;
 
     if (res.error) {
-      throw new Exception(res.data);
+      throw new Error(res.data);
     }
     return res.data;
   };
diff --git a/src/ui/dataMenu.js b/src/ui/dataMenu.js
index 456b97b..7ea0d2c 100644
--- a/src/ui/dataMenu.js
+++ b/src/ui/dataMenu.js
@@ -10,12 +10,12 @@ export class DataMenu {
       "⚠️  Codex does not encrypt files. Anything uploaded will be available publicly on testnet.",
     );
 
-    const filePath = this.ui.askPrompt("Enter the file path");
+    const filePath = await this.ui.askPrompt("Enter the file path");
     if (!this.fs.isFile(filePath)) {
       this.ui.showErrorMessage("File not found");
     } else {
       try {
-        const cid = this.dataService.upload(filePath);
+        const cid = await this.dataService.upload(filePath);
         this.ui.showInfoMessage(`Upload successful.\n CID: '${cid}'`);
       } catch (exception) {
         this.ui.showErrorMessage("Error during upload: " + exception);
@@ -24,10 +24,10 @@ export class DataMenu {
   };
 
   performDownload = async () => {
-    const cid = this.ui.askPrompt("Enter the CID");
+    const cid = await this.ui.askPrompt("Enter the CID");
     if (cid.length < 1) return;
     try {
-      const filename = this.dataService.download(cid);
+      const filename = await this.dataService.download(cid);
       this.ui.showInfoMessage(`Download successful.\n File: '${filename}'`);
     } catch (exception) {
       this.ui.showErrorMessage("Error during download: " + exception);