diff --git a/app/js/app_v3.js b/app/js/app_v3.js
index 9a49a9b..4c9ccc6 100644
--- a/app/js/app_v3.js
+++ b/app/js/app_v3.js
@@ -71,12 +71,87 @@ exports.load_config = function () {
 }
 
 
+// Check local hash file cache
+// Updated 2022-03-09
+exports.check_hash_file_cache = async function ({host_file_cache_path, hash}) {
+    console.log('*** Electron framework export: check_hash_file_cache() ***');
+    console.log('Check local hash file cache');
+    console.log(`Host File Cache Path: ${host_file_cache_path}; Hash: ${hash}`);
+
+    let hash_filename = `${hash}.file`;
+
+    let hash_file_cache_path = path.join(host_file_cache_path, hash_filename);
+    console.log(hash_file_cache_path);
+
+    if (fs.existsSync(hash_file_cache_path)) {
+        console.log(`Hashed file cache already exists: ${hash_file_cache_path}`);
+        return true;
+    } else {
+        return false;
+    }
+}
+
+// Download hash file to cache
+// Updated 2022-03-09
+exports.download_hash_file_to_cache = async function ({host_file_cache_path, event_file_id=null, hash=null}) {
+    console.log('*** Electron framework export: download_hash_file_to_cache() ***');
+    console.log('Download hash file to cache');
+    console.log(`Host File Cache Path: ${host_file_cache_path}; Event File ID: ${event_file_id}; Hash: ${hash}`);
+
+    let endpoint = `/event/file/${event_file_id}/download`;
+
+    let hash_filename = `${hash}.file`;
+    let hash_file_cache_path = path.join(host_file_cache_path, hash_filename);
+    console.log(hash_file_cache_path);
+
+    let download_file_result = await ipcRenderer.invoke('download_file', api_base_url, endpoint, hash_file_cache_path).then((result) => {
+        console.log('IPC download file process finished');
+        console.log(result);
+        return true;
+    });
+
+    console.log(download_file_result);
+    console.log('End: download_hash_file_to_cache()');
+    if (download_file_result) {
+        console.log('File downloaded successfully');
+        return true;
+    } else {
+        console.log('File was not downloaded successfully');
+        return false;
+    }
+}
+
+// Open cached hash file after copying to temp directory
+// Updated 2022-03-07
+exports.open_hash_file_to_temp = async function ({host_file_cache_path, hash, host_file_temp_path, filename}) {
+    console.log('*** Electron framework export: open_hash_file_to_temp() ***');
+    console.log('Open cached hash file after copying to temp directory');
+    console.log(`Host File Cache Path: ${host_file_cache_path}; Hash: ${hash}; Host File Temp Path: ${host_file_temp_path}; Filename: ${filename}`);
+
+    ipcRenderer.invoke('open_hash_file_to_temp', host_file_cache_path, hash, host_file_temp_path, filename).then((result) => {
+        console.log('IPC open hash file to temp finished');
+        console.log(result);
+        return false;
+    })
+
+    // let result = await ipcRenderer.send('open_local_file', host_file_cache_path, hash, host_file_temp_path, filename);
+    // console.log(result);
+
+    // return true;
+    console.log('End: open_hash_file_to_temp()');
+}
+
+
+
+// Check local file cache and download from server if needed.
+// Updated 2022-03-09
 // exports.check_file_cache = async function ({host_file_cache_path, event_file_id, hash}) {
 exports.check_file_cache = async function ({host_file_cache_path, event_file_id, hash}) {
-    console.log('*** Electron framework: check_file_cache() ***');
-    console.log('Checking the local file cache against the remote server.');
+    console.log('*** Electron framework export: check_file_cache() ***');
+    console.log('Check local file cache and download from server if needed.');
+    console.log(`Host File Cache Path: ${host_file_cache_path}; Event File ID: ${event_file_id}; Hash: ${hash}`);
 
-    event_file_id; // NOTE: This is the event_file.id_random or event_file.event_file_id_random
+    // NOTE: event_file_id is the event_file.id_random or event_file.event_file_id_random
     let hash_filename = hash+'.file';
 
     let save_path = path.join(host_file_cache_path, hash_filename);
@@ -123,29 +198,16 @@ exports.check_file_cache = async function ({host_file_cache_path, event_file_id,
     }
 }
 
-/* Updated 2022-03-07 */
-// function open_local_file({hash, host_file_cache_path, filename}) {
-exports.open_local_file = async function ({host_file_cache_path, hash, host_file_temp_path, filename}) {
-    console.log('*** Electron framework: open_local_file() ***');
-
-    console.log(host_file_cache_path);
-    console.log(hash);
-    console.log(filename);
-
-    let result = await ipcRenderer.send('open_local_file', host_file_cache_path, hash, host_file_temp_path, filename);
-    console.log(result);
-
-    return true;
-}
-
-
 
 
+// Check local file cache and download from server if needed. Must use IPC to Main to download file. Set a Promise to wait for download_file_reply.
+// Updated 2022-03-09
 async function check_file_cache({host_file_cache_path, event_file_id, hash}) {
     console.log('*** Electron framework: check_file_cache() ***');
-    console.log('Checking the local file cache against the remote server.');
+    console.log('Check local file cache and download from server if needed.');
+    console.log(`Host File Cache Path: ${host_file_cache_path}; Event File ID: ${event_file_id}; Hash: ${hash}`);
 
-    event_file_id; // NOTE: This is the event_file.id_random or event_file.event_file_id_random
+    // NOTE: event_file_id is the event_file.id_random or event_file.event_file_id_random
     let hash_filename = hash+'.file';
 
     let save_path = path.join(host_file_cache_path, hash_filename);
@@ -192,8 +254,12 @@ async function check_file_cache({host_file_cache_path, event_file_id, hash}) {
     }
 }
 
+// IPC to Main: Open local file cache if available. Copy to temp directory with given filename first.
+// Updated 2022-03-09
 async function open_local_file({host_file_cache_path, hash, host_file_temp_path, filename}) {
     console.log('*** Electron framework: open_local_file() ***');
+    console.log('Open local file cache if available. Copy to temp directory with given filename first.');
+    console.log(`Host File Cache Path: ${host_file_cache_path}; Hash: ${hash}; Host File Temp Path: ${host_file_temp_path}; Filename: ${filename}`);
 
     console.log(host_file_cache_path);
     console.log(hash);
@@ -211,11 +277,20 @@ exports.check_file_cache_and_open_local_file = async function ({host_file_cache_
     console.log('Checking the local file cache against the remote server and then opening the local file.');
 
     let check_file_cache_result = check_file_cache({host_file_cache_path: host_file_cache_path, event_file_id: event_file_id, hash: hash});
+    console.log(check_file_cache_result);
+
+    if (check_file_cache_result) {
+        let open_local_file_result = open_local_file({host_file_cache_path: host_file_cache_path, hash: hash, host_file_temp_path: host_file_temp_path, filename: filename});
+        console.log(open_local_file_result);
+
+        return open_local_file_result;
+    }
 
     ipcRenderer.once('download_file_reply', function(event, response){
         console.log(response);
 
         let open_local_file_result = open_local_file({host_file_cache_path: host_file_cache_path, hash: hash, host_file_temp_path: host_file_temp_path, filename: filename});
+        console.log(open_local_file_result);
 
         return open_local_file_result;
     })
diff --git a/config.json b/config.json
index 0a6826f..87e917c 100644
--- a/config.json
+++ b/config.json
@@ -1,5 +1,6 @@
 {
   "account_id": "_XY7DXtc9MY",
+  "device_id": "dbgMWS3KEHE",
   "event_id": "pjrcghqwert",
   "event_location_id": null,
   "event_session_id": null,
diff --git a/index.js b/index.js
index bd6ef6e..aeba27d 100644
--- a/index.js
+++ b/index.js
@@ -94,126 +94,96 @@ app.on('activate', () => {
 })
 
 
-// ipcMain.on('download_file', (event, api_base_url, api_endpoint, api_temporary_token, save_path) => {
-ipcMain.on('download_file', async (event, api_base_url, api_endpoint, save_path) => {
-    console.log('*** call IPC download_file() ***');
+// Download file to path
+// full_save_path should be the full path that includes the filename
+// Updated 2022-03-09
+ipcMain.handle('download_file', async (event, api_base_url, api_endpoint, full_save_path) => {
+    console.log('*** Electron IPC Main: download_file() ***');
     // console.log('ipcMain on download_file: api_base_url='+api_base_url+' | api_temporary_token='+api_temporary_token);
     console.log('ipcMain on download_file: api_base_url='+api_base_url);
-    // console.log(api_temporary_token);
-    console.log('ipcMain download and save file: HTTP '+api_endpoint+' -> FILE '+save_path);
+    console.log('ipcMain download and save file: HTTP '+api_endpoint+' -> FILE '+full_save_path);
 
-    let result = await download_file(api_base_url, api_endpoint, save_path);
-    event.sender.send('download_file_reply', result);
+    let result = await download_file(api_base_url, api_endpoint, full_save_path);
 
-    // axios.defaults.baseURL = api_base_url;
-    // axios.defaults.headers.common['Access-Control-Allow-Origin'] = '*'; // app_config.access_control_allow_origin;
-    // axios.defaults.headers.common['content-type'] = 'application/json';
-    // axios.defaults.headers.common['x-aether-api-key'] = 'dFP6J9DVj9hUgIMn-fNIqg'; // api_secret_key;
-    // axios.defaults.headers.common['x-account-id'] = '_XY7DXtc9MY'; // account_id;
-
-    // const url = api_endpoint;
-
-    // const writer = fs.createWriteStream(save_path);
-
-    // await axios({
-    //     method: 'get',
-    //     url: url,
-    //     responseType: 'stream' /* responseType must be stream */
-    // }).then(function (response) {
-    //     console.log('Downloading...?');
-    //     // response.data.pipe(fs.createWriteStream(save_path));
-    //     // return true;
-
-    //     return new Promise((resolve, reject) => {
-    //         response.data.pipe(writer);
-    //         let error = null;
-    //         writer.on('error', err => {
-    //             console.log('Writer error!');
-    //             error = err;
-    //             writer.close();
-    //             reject(err);
-    //         });
-    //         writer.on('close', () => {
-    //             console.log('Writer close!');
-    //             if (!error) {
-    //                 resolve(true);
-    //             }
-    //             //no need to call the reject here, as it will have been called in the
-    //             //'error' stream;
-    //         });
-    //     });
-    // })
-    // .catch(function (error) {
-    //     if (error.response && error.response.status === 404) {
-    //         return null; // Returning null since there were no results
-    //     }
-    //     console.log(`Response Status: ${error.response.status}; Status Text: ${error.response.statusText}`);
-    //     // console.log(error);
-    //     return false; // Returning false since something may have gone wrong. Also more in line with what the API returns.
-    // });
-
-    // event.sender.send('asynchronous-reply', true);
+    console.log(result);
+    console.log('End: Electron IPC Main: download_file()');
+    // return 'Return from Electron IPC Main download_file()';
+    return result;
 });
 
-async function download_file(api_base_url, api_endpoint, save_path) {
-    return new Promise((resolve, reject) => {
 
-        axios.defaults.baseURL = api_base_url;
-        axios.defaults.headers.common['Access-Control-Allow-Origin'] = '*'; // app_config.access_control_allow_origin;
-        axios.defaults.headers.common['content-type'] = 'application/json';
-        axios.defaults.headers.common['x-aether-api-key'] = 'dFP6J9DVj9hUgIMn-fNIqg'; // api_secret_key;
-        axios.defaults.headers.common['x-account-id'] = '_XY7DXtc9MY'; // account_id;
+// Download file to path
+// full_save_path should be the full path that includes the filename
+// Updated 2022-03-09
+async function download_file(api_base_url, api_endpoint, full_save_path) {
+    console.log('*** node.js: download_file() ***');
 
-        const url = api_endpoint;
+    axios.defaults.baseURL = api_base_url;
+    axios.defaults.headers.common['Access-Control-Allow-Origin'] = '*'; // app_config.access_control_allow_origin;
+    axios.defaults.headers.common['content-type'] = 'application/json';
+    axios.defaults.headers.common['x-aether-api-key'] = 'dFP6J9DVj9hUgIMn-fNIqg'; // api_secret_key;
+    axios.defaults.headers.common['x-account-id'] = '_XY7DXtc9MY'; // account_id;
 
-        const writer = fs.createWriteStream(save_path);
+    const url = api_endpoint;
 
-        let result = axios({
-            method: 'get',
-            url: url,
-            responseType: 'stream' /* responseType must be stream */
-        }).then(function (response) {
-            console.log('Downloading...?');
-            // response.data.pipe(fs.createWriteStream(save_path));
-            // return true;
+    let result = await axios({
+        method: 'get',
+        url: url,
+        responseType: 'stream' /* responseType must be stream */
+    }).then(function (response) {
+        console.log('Downloading...');
+        // response.data.pipe(fs.createWriteStream(full_save_path));
+        // return true;
 
-            return new Promise((resolve, reject) => {
-                response.data.pipe(writer);
-                let error = null;
-                writer.on('error', err => {
-                    console.log('Writer error!');
-                    error = err;
-                    writer.close();
-                    reject(err);
-                });
-                writer.on('close', () => {
-                    console.log('Writer close!');
-                    if (!error) {
-                        resolve(true);
-                    }
-                    //no need to call the reject here, as it will have been called in the
-                    //'error' stream;
-                });
-            });
-        })
-        .catch(function (error) {
-            if (error.response && error.response.status === 404) {
-                return null; // Returning null since there were no results
-            }
-            console.log(`Response Status: ${error.response.status}; Status Text: ${error.response.statusText}`);
-            // console.log(error);
-            return false; // Returning false since something may have gone wrong. Also more in line with what the API returns.
-        });
+        response.data.pipe(fs.createWriteStream(full_save_path));
+        return true;
 
-      resolve(result)
+        // const writer = fs.createWriteStream(full_save_path);
+
+        // console.log('Write stream created');
+
+        // return new Promise((resolve, reject) => {
+        //     response.data.pipe(writer);
+        //     let error = null;
+        //     writer.on('error', err => {
+        //         console.log('Writer error!');
+        //         error = err;
+        //         console.log(error);
+        //         writer.close();
+        //         reject(err);
+        //     });
+        //     writer.on('close', () => {
+        //         console.log('Writer close!');
+        //         if (!error) {
+        //             resolve(true);
+        //         }
+        //         //no need to call the reject here, as it will have been called in the
+        //         //'error' stream;
+        //     });
+        // });
     })
-  }
+    .catch(function (error) {
+        console.log(`Error downloading! Endpoint: ${api_endpoint}`);
+        // console.log(error);
+        // console.log(error.response);
+        if (error.response && error.response.status === 404) {
+            return null; // Returning null since there were no results
+        }
+        console.log(`Response Status: ${error.response.status}; Status Text: ${error.response.statusText}`);
+        return false; // Returning false since something may have gone wrong. Also more in line with what the API returns.
+    });
+
+    console.log(result);
+    console.log('End: download_file()');
+    // return 'Return from download_file()';
+    return result;
+}
 
 
-// ipcMain.on('open_local_file', (event, file_path, filename) => {
-// ipcMain.on('open_local_file', ({host_file_cache_path, hash, filename}) => {
-ipcMain.on('open_local_file', (event, host_file_cache_path, hash, host_file_temp_path, filename) => {
-    console.log('ipcMain open local file: '+host_file_cache_path+' -> '+filename);
+ipcMain.handle('open_hash_file_to_temp', async (event, host_file_cache_path, hash, host_file_temp_path, filename) => {
+    console.log('*** Electron IPC Main: open_hash_file_to_temp() ***');
+    console.log('ipcMain on open_hash_file_to_temp');
+    console.log(`ipcMain open hash file from temp directory: ${host_file_cache_path} -> ${host_file_temp_path}/${filename}`);
 
     let cache_file_path = path.join(process.cwd(), host_file_cache_path);
     console.log(cache_file_path);
@@ -248,9 +218,15 @@ ipcMain.on('open_local_file', (event, host_file_cache_path, hash, host_file_temp
         return false;
     }
 
-    shell.openPath(open_temp_file_path);
-    //fs.open(open_temp_file_path);
-    // return true;
+    try {
+        shell.openPath(open_temp_file_path);
+    } catch (error) {
+        console.error(error);
+        return false;
+    }
 
-    event.sender.send('asynchronous-reply', true);
+    console.log(true);
+    console.log('End: Electron IPC Main: open_hash_file_to_temp()');
+    return 'Return from Electron IPC Main open_hash_file_to_temp()';
+    // return result;
 });