diff --git a/main/src/index.ts b/main/src/index.ts
index 4cbd0ebe..6476845f 100644
--- a/main/src/index.ts
+++ b/main/src/index.ts
@@ -2,12 +2,15 @@ import { app, ipcMain, IpcMainEvent, remote } from 'electron';
 import * as path from 'path';
 import * as url from 'url';
 import * as fse from 'fs-extra';
+import * as fs from 'fs';
 
 import { AppWindow } from './app/AppWindow';
 import { now } from './util/now';
 import { showUncaughtException } from './crash/show-uncaught-exception';
 import { Channel } from '@ucap-webmessenger/native-electron';
 import { root } from './util/root';
+import { DefaultFolder } from './lib/default-folder';
+import { FileUtil } from './lib/file-util';
 
 let appWindow: AppWindow | null = null;
 
@@ -179,19 +182,37 @@ ipcMain.on(Channel.checkForUpdates, (event: IpcMainEvent, ...args: any[]) => {
 
 ipcMain.on(Channel.readFile, (event: IpcMainEvent, ...args: any[]) => {
   try {
-    const rBuf = fse.readFileSync(root(args[0]));
-    event.returnValue = rBuf.buffer;
+    fse.readFile(root(args[0]), (err, data) => {
+      if (!!err) {
+        event.returnValue = null;
+      } else {
+        event.returnValue = new Blob([data]);
+      }
+    });
   } catch (error) {
     event.returnValue = null;
   }
 });
 
-ipcMain.on(Channel.saveFile, (event: IpcMainEvent, ...args: any[]) => {
+ipcMain.on(Channel.saveFile, async (event: IpcMainEvent, ...args: any[]) => {
   try {
-    fse.writeFileSync(root(args[0]), args[1]);
-    event.returnValue = true;
+    const buffer: Buffer = args[0];
+    const fileName: string = args[1];
+    let savePath: string = path.join(
+      !!args[2] ? args[2] : DefaultFolder.downloads(),
+      fileName
+    );
+    savePath = await FileUtil.uniqueFileName(savePath);
+
+    fse.writeFile(savePath, buffer, err => {
+      if (!err) {
+        event.returnValue = savePath;
+      } else {
+        event.returnValue = undefined;
+      }
+    });
   } catch (error) {
-    event.returnValue = false;
+    event.returnValue = undefined;
   }
 });
 
diff --git a/main/src/lib/default-folder.ts b/main/src/lib/default-folder.ts
new file mode 100644
index 00000000..6a8e659d
--- /dev/null
+++ b/main/src/lib/default-folder.ts
@@ -0,0 +1,37 @@
+import * as os from 'os';
+import { execSync } from 'child_process';
+import * as fse from 'fs-extra';
+
+export class DefaultFolder {
+  static downloads(): string {
+    switch (os.platform()) {
+      case 'win32':
+        return `${process.env.USERPROFILE}/Downloads`;
+      case 'darwin':
+        return `${process.env.HOME}/Downloads`;
+      case 'linux': {
+        let dir: Buffer;
+        try {
+          dir = execSync('xdg-user-dir DOWNLOAD', { stdio: [0, 3, 3] });
+        } catch (_) {}
+
+        if (dir) {
+          return dir.toString('utf-8');
+        }
+
+        let stat: fse.Stats;
+        const homeDownloads = `${process.env.HOME}/Downloads`;
+        try {
+          stat = fse.statSync(homeDownloads);
+        } catch (_) {}
+        if (stat) {
+          return homeDownloads;
+        }
+        return '/tmp/';
+      }
+
+      default:
+        break;
+    }
+  }
+}
diff --git a/main/src/lib/file-util.ts b/main/src/lib/file-util.ts
new file mode 100644
index 00000000..64e46a28
--- /dev/null
+++ b/main/src/lib/file-util.ts
@@ -0,0 +1,222 @@
+import * as path from 'path';
+import * as fse from 'fs-extra';
+
+/**
+ *
+ * separator
+ * If the specified filename exists, the separator will be added before the incremental value such as: file{separator}2.jpg
+ * The default value is '-'.
+ *
+ * mode
+ * The mode allows you to specify which characters to use to generate the incremental value (the string after the separator)
+ * The default value is 'numeric'.
+ * 'numeric' Using the following characters: 1234567890
+ * 'alpha' Using the following characters: abcdefghijklmnopqrstuvwxyz
+ * 'ALPHA' Using the following characters: ABCDEFGHIJKLMNOPQRSTUVWXYZ
+ * 'alphanumeric' Using the following characters: 0123456789abcdefghijklmnopqrstuvwxyz
+ * 'ALPHANUMERIC' Using the following characters: 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ
+ * 'charset' You must specify the characters you wish to use in the charset option
+ *
+ * paddingCharacter && paddingSize
+ * If you wish to left-pad the incremental values with a character, use this option. Here's an example :
+ * var uniquefilename = require('uniquefilename');
+ * options = {mode: 'alpha', paddingCharacter: '0', paddingSize: 3};
+ * uniquefilename.get('/path/to/dir/file.jpg', options, function(filename) {
+ *   // filename might be "/path/to/dir/file.jpg",
+ *   // "/path/to/dir/file-002.jpg", "/path/to/dir/file-045.jpg", etc...
+ *   // depending on the files that exist on your filesystem
+ * });
+ *
+ * alwaysAppend
+ * If alwaysAppend is true filenames will include the separator and attachment from the first request.
+ * So instead of file.jpg, file-2.jpg you'd get file-1.jpg, file-2.jpg.
+ */
+export interface UniqueFileNameOption {
+  separator?: string;
+  mode?:
+    | 'numeric'
+    | 'alpha'
+    | 'ALPHA'
+    | 'alphanumeric'
+    | 'ALPHANUMERIC'
+    | 'charset';
+  paddingCharacter?: string;
+  paddingSize?: number;
+  alwaysAppend?: boolean;
+  charset?: string;
+}
+
+const charsets = {
+  alpha: 'abcdefghijklmnopqrstuvwxyz',
+  alphanumeric: '0123456789abcdefghijklmnopqrstuvwxyz',
+  ALPHA: 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
+  ALPHANUMERIC: '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+};
+
+interface UniqueFile {
+  dir?: string;
+  ext?: string;
+  base?: string;
+  increment?: number;
+}
+
+export class FileUtil {
+  static blobToBuffer(blob: Blob): Promise<Buffer> {
+    if (typeof Blob === 'undefined' || !(blob instanceof Blob)) {
+      throw new Error('first argument must be a Blob');
+    }
+
+    return new Promise<Buffer>((resolve, reject) => {
+      const reader = new FileReader();
+      reader.onloadend = () => {
+        resolve(Buffer.from(reader.result as ArrayBuffer));
+      };
+      reader.onerror = () => {
+        reader.abort();
+        reject(reader.error);
+      };
+      reader.readAsArrayBuffer(blob);
+    });
+  }
+
+  static uniqueFileName(
+    filePath: string,
+    options?: UniqueFileNameOption
+  ): Promise<string> {
+    return new Promise<string>((resolve, reject) => {
+      const dir = path.dirname(filePath);
+      const ext = path.extname(filePath);
+      const base = path.basename(filePath, ext);
+
+      const uniqueFile: UniqueFile = {
+        dir,
+        ext,
+        base
+      };
+
+      options = options || {};
+      options.separator = options.separator || '-';
+      options.mode = options.mode || 'numeric';
+
+      if ('numeric' !== options.mode) {
+        if (charsets[options.mode]) {
+          options.charset = charsets[options.mode];
+          options.mode = 'charset';
+        } else if (
+          'charset' !== options.mode ||
+          ('charset' === options.mode && !options.charset)
+        ) {
+          options.mode = 'numeric';
+        }
+      }
+
+      if (options.paddingSize && !options.paddingCharacter) {
+        options.paddingCharacter = '0';
+      }
+
+      FileUtil.uniqueFileNameProcess(
+        uniqueFile,
+        options,
+        (fileName: string) => {
+          resolve(fileName);
+        }
+      );
+    });
+  }
+
+  private static uniqueFileNameProcess(
+    uniqueFile: UniqueFile,
+    options: UniqueFileNameOption,
+    callback: (fileName: string) => void
+  ) {
+    let fileName: string;
+    let append = '';
+
+    if (options.alwaysAppend && !uniqueFile.increment) {
+      uniqueFile.increment = 1;
+    }
+
+    if (uniqueFile.increment) {
+      if ('numeric' === options.mode) {
+        append = '' + uniqueFile.increment;
+      } else {
+        append = FileUtil.numberToString(uniqueFile.increment, options.charset);
+      }
+
+      if (options.paddingSize) {
+        while (append.length < options.paddingSize) {
+          append = options.paddingCharacter + append;
+        }
+      }
+
+      append = options.separator + append;
+    }
+
+    fileName = path.join(
+      uniqueFile.dir,
+      uniqueFile.base + append + uniqueFile.ext
+    );
+    if (fse.existsSync(fileName)) {
+      if (uniqueFile.increment) {
+        uniqueFile.increment += 1;
+      } else {
+        uniqueFile.increment = 'numeric' === options.mode ? 2 : 1;
+      }
+      return FileUtil.uniqueFileNameProcess(uniqueFile, options, callback);
+    } else {
+      return callback(fileName);
+    }
+  }
+
+  private static numberToString(nbr: number, charset: string) {
+    const charsetLen = charset.length;
+    let strLen = 0;
+    let strThisLen = 0;
+    let tmp: number;
+
+    for (let maxpower = 20; maxpower >= 0; maxpower--) {
+      const maxvalue = FileUtil.sumOfPowerFromOne(charsetLen, maxpower);
+
+      if (maxvalue < nbr) {
+        strLen = maxpower + 1;
+        strThisLen = maxvalue + Math.pow(charsetLen, maxpower + 1) - maxvalue;
+
+        break;
+      }
+    }
+
+    if (0 === strLen) {
+      return null;
+    }
+
+    let str = '';
+    while (--strLen >= 0) {
+      if (strLen === 0) {
+        str += charset.charAt(nbr - 1);
+        break;
+      }
+
+      strThisLen = Math.pow(charsetLen, strLen);
+      const initial = FileUtil.sumOfPowerFromOne(charsetLen, strLen - 1);
+
+      for (tmp = charsetLen; tmp >= 1; tmp--) {
+        if (initial + tmp * strThisLen < nbr) {
+          break;
+        }
+      }
+
+      nbr -= tmp * strThisLen;
+      str += charset.charAt(tmp - 1);
+    }
+
+    return str;
+  }
+
+  private static sumOfPowerFromOne(base: number, maxpower: number) {
+    let value = 0;
+    for (let tmp = maxpower; tmp >= 1; tmp--) {
+      value += Math.pow(base, tmp);
+    }
+    return value;
+  }
+}
diff --git a/projects/ucap-webmessenger-app/src/app/layouts/common/dialogs/file-viewer.dialog.component.ts b/projects/ucap-webmessenger-app/src/app/layouts/common/dialogs/file-viewer.dialog.component.ts
index cdbe1ac4..b0cc6383 100644
--- a/projects/ucap-webmessenger-app/src/app/layouts/common/dialogs/file-viewer.dialog.component.ts
+++ b/projects/ucap-webmessenger-app/src/app/layouts/common/dialogs/file-viewer.dialog.component.ts
@@ -9,8 +9,10 @@ import {
 import { MatDialogRef, MAT_DIALOG_DATA } from '@angular/material';
 import { NGXLogger } from 'ngx-logger';
 import { FileEventJson } from '@ucap-webmessenger/protocol-event';
-import { DeviceType } from '@ucap-webmessenger/core';
-import * as FileSaver from 'file-saver';
+import { DeviceType, FileUtil } from '@ucap-webmessenger/core';
+import { NativeService, UCAP_NATIVE_SERVICE } from '@ucap-webmessenger/native';
+import { take } from 'rxjs/operators';
+import { SnackBarService } from '@ucap-webmessenger/ui';
 
 export interface FileViewerDialogData {
   fileInfo: FileEventJson;
@@ -40,6 +42,8 @@ export class FileViewerDialogComponent implements OnInit, OnDestroy {
       FileViewerDialogResult
     >,
     @Inject(MAT_DIALOG_DATA) public data: FileViewerDialogData,
+    @Inject(UCAP_NATIVE_SERVICE) private nativeService: NativeService,
+    private snackBarService: SnackBarService,
     private logger: NGXLogger
   ) {
     this.fileInfo = data.fileInfo;
@@ -54,7 +58,29 @@ export class FileViewerDialogComponent implements OnInit, OnDestroy {
   ngOnDestroy(): void {}
 
   onDownload(blob: Blob): void {
-    FileSaver.saveAs(blob, this.fileInfo.fileName);
+    FileUtil.fromBlobToBuffer(blob)
+      .then(buffer => {
+        this.nativeService
+          .saveFile(buffer, this.fileInfo.fileName)
+          .pipe(take(1))
+          .subscribe(result => {
+            if (!!result) {
+              this.snackBarService.open(
+                `파일이 경로[${result}]에 저장되었습니다.`,
+                '',
+                {
+                  duration: 3000,
+                  verticalPosition: 'bottom'
+                }
+              );
+            } else {
+              this.snackBarService.open('파일 저장에 실패하였습니다.');
+            }
+          });
+      })
+      .catch(reason => {
+        this.logger.error('download', reason);
+      });
   }
 
   onClosedViewer(): void {
diff --git a/projects/ucap-webmessenger-core/src/lib/utils/file.util.ts b/projects/ucap-webmessenger-core/src/lib/utils/file.util.ts
index 2d215ea3..7f4411c8 100644
--- a/projects/ucap-webmessenger-core/src/lib/utils/file.util.ts
+++ b/projects/ucap-webmessenger-core/src/lib/utils/file.util.ts
@@ -14,11 +14,9 @@ export class FileUtil {
     return extensions;
   }
 
-  static toDataUrl(blob: Blob): Promise<string | ArrayBuffer> {
+  static fromBlobToDataUrl(blob: Blob): Promise<string | ArrayBuffer> {
     return new Promise<string | ArrayBuffer>((resolve, reject) => {
       const fileReader = new FileReader();
-      fileReader.readAsDataURL(blob);
-
       fileReader.onload = () => {
         return resolve(fileReader.result);
       };
@@ -26,6 +24,35 @@ export class FileUtil {
         fileReader.abort();
         return reject(fileReader.error);
       };
+      fileReader.readAsDataURL(blob);
+    });
+  }
+
+  static fromBlobToBuffer(blob: Blob): Promise<Buffer> {
+    return new Promise<Buffer>((resolve, reject) => {
+      const fileReader = new FileReader();
+      fileReader.onload = () => {
+        return resolve(Buffer.from(fileReader.result as ArrayBuffer));
+      };
+      fileReader.onerror = (event: ProgressEvent) => {
+        fileReader.abort();
+        return reject(fileReader.error);
+      };
+      fileReader.readAsArrayBuffer(blob);
+    });
+  }
+
+  static fromBlobToString(blob: Blob): Promise<string> {
+    return new Promise<string>((resolve, reject) => {
+      const fileReader = new FileReader();
+      fileReader.onload = () => {
+        return resolve(fileReader.result.toString());
+      };
+      fileReader.onerror = (event: ProgressEvent) => {
+        fileReader.abort();
+        return reject(fileReader.error);
+      };
+      fileReader.readAsArrayBuffer(blob);
     });
   }
 }
diff --git a/projects/ucap-webmessenger-native-browser/src/lib/services/browser-native.service.ts b/projects/ucap-webmessenger-native-browser/src/lib/services/browser-native.service.ts
index 9c73c342..1c3d3214 100644
--- a/projects/ucap-webmessenger-native-browser/src/lib/services/browser-native.service.ts
+++ b/projects/ucap-webmessenger-native-browser/src/lib/services/browser-native.service.ts
@@ -25,12 +25,20 @@ export class BrowserNativeService implements NativeService {
 
   showImageViewer(): void {}
 
-  readFile(path: string): Observable<ArrayBuffer> {
-    return this.httpClient.get(path, { responseType: 'arraybuffer' });
+  readFile(path: string): Observable<Buffer> {
+    return this.httpClient.get(path, { responseType: 'arraybuffer' }).pipe(
+      map(arrayBuffer => {
+        return Buffer.from(arrayBuffer);
+      })
+    );
   }
 
-  saveFile(path: string, buf: ArrayBuffer): Observable<boolean> {
-    return this.httpClient.post<boolean>(path, buf, {});
+  saveFile(
+    buffer: Buffer,
+    fileName: string,
+    path?: string
+  ): Observable<string> {
+    return this.httpClient.post<string>(path, buffer, {});
   }
 
   windowStateChanged(): Observable<WindowState> {
diff --git a/projects/ucap-webmessenger-native-browser/src/lib/translate/browser-loader.ts b/projects/ucap-webmessenger-native-browser/src/lib/translate/browser-loader.ts
index d927e114..75e2bb37 100644
--- a/projects/ucap-webmessenger-native-browser/src/lib/translate/browser-loader.ts
+++ b/projects/ucap-webmessenger-native-browser/src/lib/translate/browser-loader.ts
@@ -2,6 +2,7 @@ import { TranslateLoader } from '@ngx-translate/core';
 import { Observable } from 'rxjs';
 import { NativeService } from '@ucap-webmessenger/native';
 import { take, map } from 'rxjs/operators';
+import { FileUtil } from '@ucap-webmessenger/core';
 
 export class TranslateBrowserLoader implements TranslateLoader {
   constructor(
@@ -18,8 +19,8 @@ export class TranslateBrowserLoader implements TranslateLoader {
       .readFile(`${this.prefix}${lang}.${this.suffix}`)
       .pipe(
         take(1),
-        map(buf => {
-          return JSON.parse(Buffer.from(buf).toString('utf8'));
+        map(buffer => {
+          return JSON.parse(buffer.toString('utf-8'));
         })
       );
   }
diff --git a/projects/ucap-webmessenger-native-electron/src/lib/services/electron-native.service.ts b/projects/ucap-webmessenger-native-electron/src/lib/services/electron-native.service.ts
index 28b1e5a8..39a41285 100644
--- a/projects/ucap-webmessenger-native-electron/src/lib/services/electron-native.service.ts
+++ b/projects/ucap-webmessenger-native-electron/src/lib/services/electron-native.service.ts
@@ -42,8 +42,8 @@ export class ElectronNativeService implements NativeService {
     ipcRenderer.send(Channel.showImageViewer);
   }
 
-  readFile(path: string): Observable<ArrayBuffer> {
-    return new Observable<ArrayBuffer>(subscriber => {
+  readFile(path: string): Observable<Buffer> {
+    return new Observable<Buffer>(subscriber => {
       try {
         subscriber.next(ipcRenderer.sendSync(Channel.readFile, path));
       } catch (error) {
@@ -54,10 +54,16 @@ export class ElectronNativeService implements NativeService {
     });
   }
 
-  saveFile(path: string, buf: ArrayBuffer): Observable<boolean> {
-    return new Observable<boolean>(subscriber => {
+  saveFile(
+    buffer: Buffer,
+    fileName: string,
+    path?: string
+  ): Observable<string> {
+    return new Observable<string>(subscriber => {
       try {
-        subscriber.next(ipcRenderer.sendSync(Channel.saveFile, path, buf));
+        subscriber.next(
+          ipcRenderer.sendSync(Channel.saveFile, buffer, fileName, path)
+        );
       } catch (error) {
         subscriber.error(error);
       } finally {
diff --git a/projects/ucap-webmessenger-native/src/lib/services/native.service.ts b/projects/ucap-webmessenger-native/src/lib/services/native.service.ts
index 1944c2f8..4518cef0 100644
--- a/projects/ucap-webmessenger-native/src/lib/services/native.service.ts
+++ b/projects/ucap-webmessenger-native/src/lib/services/native.service.ts
@@ -9,8 +9,8 @@ export interface NativeService {
 
   showImageViewer(): void;
 
-  saveFile(path: string, buf: ArrayBuffer): Observable<boolean>;
-  readFile(path: string): Observable<ArrayBuffer>;
+  saveFile(buffer: Buffer, fileName: string, path?: string): Observable<string>;
+  readFile(path: string): Observable<Buffer>;
 
   windowStateChanged(): Observable<WindowState>;
   windowClose(): void;
diff --git a/projects/ucap-webmessenger-ui/src/lib/components/file-viewer/image-viewer.component.ts b/projects/ucap-webmessenger-ui/src/lib/components/file-viewer/image-viewer.component.ts
index c766fed1..e680e572 100644
--- a/projects/ucap-webmessenger-ui/src/lib/components/file-viewer/image-viewer.component.ts
+++ b/projects/ucap-webmessenger-ui/src/lib/components/file-viewer/image-viewer.component.ts
@@ -69,7 +69,7 @@ export class ImageViewerComponent implements OnInit {
             blob.size,
             MimeUtil.getMimeFromExtension(this.fileInfo.fileExt)
           );
-          this.imageSrc = await FileUtil.toDataUrl(this.blob);
+          this.imageSrc = await FileUtil.fromBlobToDataUrl(this.blob);
         })
       )
       .subscribe();