diff --git a/src/components/settings/app.tsx b/src/components/settings/app.tsx
index 6b8d0da..24ccfe0 100644
--- a/src/components/settings/app.tsx
+++ b/src/components/settings/app.tsx
@@ -1,8 +1,9 @@
 import * as React from "react"
 import intl = require("react-intl-universal")
 import { urlTest } from "../../scripts/utils"
-import { getProxy, getProxyStatus, toggleProxyStatus, setProxy, getThemeSettings, setThemeSettings, ThemeSettings, getLocaleSettings } from "../../scripts/settings"
-import { Stack, Label, Toggle, TextField, DefaultButton, ChoiceGroup, IChoiceGroupOption, loadTheme, Dropdown, IDropdownOption } from "@fluentui/react"
+import { getProxy, getProxyStatus, toggleProxyStatus, setProxy, getThemeSettings, setThemeSettings, ThemeSettings, getLocaleSettings, exportAll } from "../../scripts/settings"
+import { Stack, Label, Toggle, TextField, DefaultButton, ChoiceGroup, IChoiceGroupOption, loadTheme, Dropdown, IDropdownOption, PrimaryButton } from "@fluentui/react"
+import { remote } from "electron"
 
 type AppTabProps = {
     setLanguage: (option: string) => void
@@ -50,6 +51,18 @@ class AppTab extends React.Component<AppTabProps> {
         this.setState({ themeSettings: option.key })
     }
 
+    exportAll = () => {
+        remote.dialog.showSaveDialog(
+            remote.getCurrentWindow(),
+            {
+                defaultPath: "*/Fluent_Reader_Backup.frdata",
+                filters: [{ name: intl.get("app.frData"), extensions: ["frdata"] }]
+            }
+        ).then(result => {
+            if (!result.canceled) exportAll(result.filePath)
+        })
+    }
+
     render = () => (
         <div className="tab-body">
             <Label>{intl.get("app.language")}</Label>
@@ -96,6 +109,16 @@ class AppTab extends React.Component<AppTabProps> {
                     </Stack.Item>
                 </Stack>
             </form>}
+
+            <Label>{intl.get("app.data")}</Label>
+            <Stack horizontal>
+            <Stack.Item>
+                    <PrimaryButton onClick={this.exportAll} text={intl.get("app.backup")} />
+                </Stack.Item>
+                <Stack.Item>
+                    <DefaultButton text={intl.get("app.restore")} />
+                </Stack.Item>
+            </Stack>
         </div>
     )
 }
diff --git a/src/components/utils/article-search.tsx b/src/components/utils/article-search.tsx
index f9eacee..26a6d3a 100644
--- a/src/components/utils/article-search.tsx
+++ b/src/components/utils/article-search.tsx
@@ -2,22 +2,10 @@ import * as React from "react"
 import intl = require("react-intl-universal")
 import { connect } from "react-redux"
 import { RootState } from "../../scripts/reducer"
-import { SearchBox, IRefObject, ISearchBox } from "@fluentui/react"
+import { SearchBox, ISearchBox, Async } from "@fluentui/react"
 import { AppDispatch } from "../../scripts/utils"
 import { performSearch } from "../../scripts/models/page"
 
-class Debounced {
-    public use = (func: (...args: any[]) => any, delay: number): ((...args: any[]) => void) => {
-        let timer: NodeJS.Timeout
-        return (...args: any[]) => {
-            clearTimeout(timer)
-            timer = setTimeout(() => {
-                func.apply(this, args)
-            }, delay)
-        }
-    }
-}
-
 type SearchProps = {
     searchOn: boolean
     initQuery: string
@@ -30,7 +18,14 @@ class ArticleSearch extends React.Component<SearchProps> {
 
     constructor(props: SearchProps) {
         super(props)
-        this.debouncedSearch = new Debounced().use((query: string) => props.dispatch(performSearch(query)), 750)
+        this.debouncedSearch = new Async().debounce((query: string) => {
+            try {
+                RegExp(query)
+                props.dispatch(performSearch(query))
+            } catch {
+                // console.log("Invalid regex")
+            }
+        }, 750)
         this.inputRef = React.createRef<ISearchBox>()
     }
 
diff --git a/src/containers/settings/sources-container.tsx b/src/containers/settings/sources-container.tsx
index 8ad7115..60f3201 100644
--- a/src/containers/settings/sources-container.tsx
+++ b/src/containers/settings/sources-container.tsx
@@ -42,6 +42,7 @@ const mapDispatchToProps = (dispatch: AppDispatch) => {
             remote.dialog.showSaveDialog(
                 remote.getCurrentWindow(),
                 {
+                    defaultPath: "*/Fluent_Reader_Export.opml",
                     filters: [{ name: intl.get("sources.opmlFile"), extensions: ["opml"] }]
                 }
             ).then(result => {
diff --git a/src/scripts/i18n/en-US.json b/src/scripts/i18n/en-US.json
index 1f5bf82..16b3484 100644
--- a/src/scripts/i18n/en-US.json
+++ b/src/scripts/i18n/en-US.json
@@ -62,6 +62,7 @@
         "manageSources": "Manage sources"
     },
     "settings": {
+        "writeError": "An error has occured while writing the file.",
         "name": "Settings",
         "fetching": "Updating sources, please wait …",
         "exit": "Exit settings",
@@ -111,6 +112,10 @@
         "groupHint": "Double click on group to edit sources. Drag and drop to reorder."
     },
     "app": {
+        "data": "Application Data",
+        "backup": "Backup",
+        "restore": "Restore",
+        "frData": "Fluent Reader Data",
         "language": "Display language",
         "theme": "Theme",
         "lightTheme": "Light mode",
diff --git a/src/scripts/i18n/zh-CN.json b/src/scripts/i18n/zh-CN.json
index e27d14f..5db08fe 100644
--- a/src/scripts/i18n/zh-CN.json
+++ b/src/scripts/i18n/zh-CN.json
@@ -62,6 +62,7 @@
         "manageSources": "管理订阅源"
     },
     "settings": {
+        "writeError": "写入文件时发生错误",
         "name": "选项",
         "fetching": "正在更新订阅源，请稍候…",
         "exit": "退出选项",
@@ -111,6 +112,10 @@
         "groupHint": "双击分组以修改订阅源，可通过拖拽排序"
     },
     "app": {
+        "data": "应用数据",
+        "backup": "备份",
+        "restore": "还原",
+        "frData": "Fluent Reader数据",
         "language": "界面语言",
         "theme": "应用主题",
         "lightTheme": "浅色模式",
diff --git a/src/scripts/models/feed.ts b/src/scripts/models/feed.ts
index dd22e46..5c7fccd 100644
--- a/src/scripts/models/feed.ts
+++ b/src/scripts/models/feed.ts
@@ -1,7 +1,7 @@
 import * as db from "../db"
 import { SourceActionTypes, INIT_SOURCES, ADD_SOURCE, DELETE_SOURCE } from "./source"
-import { ItemActionTypes, FETCH_ITEMS, RSSItem, MARK_READ, MARK_UNREAD, TOGGLE_STARRED, TOGGLE_HIDDEN, applyItemReduction } from "./item"
-import { ActionStatus, AppThunk } from "../utils"
+import { ItemActionTypes, FETCH_ITEMS, RSSItem, MARK_READ, MARK_UNREAD, TOGGLE_STARRED, TOGGLE_HIDDEN, applyItemReduction, ItemState } from "./item"
+import { ActionStatus, AppThunk, mergeSortedArrays } from "../utils"
 import { PageActionTypes, SELECT_PAGE, PageType, APPLY_FILTER } from "./page"
 
 export enum FilterType {
@@ -115,9 +115,9 @@ export type FeedState = {
     [_id: string]: RSSFeed
 }
 
-export const INIT_FEEDS = 'INIT_FEEDS'
-export const INIT_FEED = 'INIT_FEED'
-export const LOAD_MORE = 'LOAD_MORE'
+export const INIT_FEEDS = "INIT_FEEDS"
+export const INIT_FEED = "INIT_FEED"
+export const LOAD_MORE = "LOAD_MORE"
 
 interface initFeedsAction {
     type: typeof INIT_FEEDS
@@ -278,13 +278,14 @@ export function feedReducer(
                     let nextState = { ...state }
                     for (let feed of Object.values(state)) {
                         if (feed.loaded) {
-                            let iids = action.items
+                            let items = action.items
                                 .filter(i => feed.sids.includes(i.source) && FeedFilter.testItem(feed.filter, i))
-                                .map(i => i._id)
-                            if (iids.length > 0) {
+                            if (items.length > 0) {
+                                let oldItems = feed.iids.map(id => action.itemState[id])
+                                let nextItems = mergeSortedArrays(oldItems, items, (a, b) => b.date.getTime() - a.date.getTime())
                                 nextState[feed._id] = { 
                                     ...feed, 
-                                    iids: [...iids, ...feed.iids]
+                                    iids: nextItems.map(i => i._id)
                                 }
                             }
                         }
diff --git a/src/scripts/models/group.ts b/src/scripts/models/group.ts
index 1dce9ab..b07946d 100644
--- a/src/scripts/models/group.ts
+++ b/src/scripts/models/group.ts
@@ -236,7 +236,7 @@ export function importOPML(path: string): AppThunk {
                     })
                 })
                 Promise.allSettled(promises).then(() => {
-                    dispatch(fetchItemsSuccess([]))
+                    dispatch(fetchItemsSuccess([], {}))
                     dispatch(saveSettings())
                     if (errors.length > 0) {
                         remote.dialog.showErrorBox(
@@ -284,7 +284,7 @@ export function exportOPML(path: string): AppThunk {
         }
         let serializer = new XMLSerializer()
         fs.writeFile(path, serializer.serializeToString(xml), (err) => {
-            if (err) console.log(err)
+            if (err) remote.dialog.showErrorBox(intl.get("settings.writeError"), String(err))
         })
     }
     
diff --git a/src/scripts/models/item.ts b/src/scripts/models/item.ts
index 4a6c006..9af9e2e 100644
--- a/src/scripts/models/item.ts
+++ b/src/scripts/models/item.ts
@@ -2,7 +2,7 @@ import * as db from "../db"
 import intl = require("react-intl-universal")
 import { rssParser, domParser, htmlDecode, ActionStatus, AppThunk } from "../utils"
 import { RSSSource } from "./source"
-import { FeedActionTypes, INIT_FEED, LOAD_MORE, FeedFilter } from "./feed"
+import { FeedActionTypes, INIT_FEED, LOAD_MORE } from "./feed"
 import Parser = require("@yang991178/rss-parser")
 
 export class RSSItem {
@@ -64,6 +64,7 @@ interface FetchItemsAction {
     status: ActionStatus
     fetchCount?: number
     items?: RSSItem[]
+    itemState?: ItemState
     errSource?: RSSSource
     err?
 }
@@ -104,11 +105,12 @@ export function fetchItemsRequest(fetchCount = 0): ItemActionTypes {
     }
 }
 
-export function fetchItemsSuccess(items: RSSItem[]): ItemActionTypes {
+export function fetchItemsSuccess(items: RSSItem[], itemState: ItemState): ItemActionTypes {
     return {
         type: FETCH_ITEMS,
         status: ActionStatus.Success,
-        items: items
+        items: items,
+        itemState: itemState
     }
 }
 
@@ -162,7 +164,7 @@ export function fetchItems(): AppThunk<Promise<void>> {
                 })
                 insertItems(items)
                 .then(inserted => {
-                    dispatch(fetchItemsSuccess(inserted.reverse()))
+                    dispatch(fetchItemsSuccess(inserted.reverse(), getState().items))
                     resolve()
                 })
                 .catch(err => {
diff --git a/src/scripts/models/source.ts b/src/scripts/models/source.ts
index d680203..c67eee6 100644
--- a/src/scripts/models/source.ts
+++ b/src/scripts/models/source.ts
@@ -223,8 +223,7 @@ export function addSource(url: string, name: string = null, batch = false): AppT
                                 dispatch(addSourceSuccess(source, batch))
                                 RSSSource.checkItems(source, feed.items, db.idb)
                                     .then(items => insertItems(items))
-                                    .then(items => {
-                                        //dispatch(fetchItemsSuccess(items))
+                                    .then(() => {
                                         SourceGroup.save(getState().groups)
                                         resolve(source.sid)
                                     })
diff --git a/src/scripts/settings.ts b/src/scripts/settings.ts
index 76b4009..faea277 100644
--- a/src/scripts/settings.ts
+++ b/src/scripts/settings.ts
@@ -4,6 +4,8 @@ import { IPartialTheme, loadTheme } from "@fluentui/react"
 import locales from "./i18n/_locales"
 import Store = require("electron-store")
 import { schemaTypes } from "./config-schema"
+import fs = require("fs")
+import intl = require("react-intl-universal")
 
 export const store = new Store<schemaTypes>()
 
@@ -106,3 +108,28 @@ export function getCurrentLocale() {
     let locale = set === "default" ? remote.app.getLocale() : set
     return (locale in locales) ? locale : "en-US"
 }
+
+export function exportAll(path) {
+    let output = {}
+    for (let [key, value] of store) {
+        output[key] = value
+    }
+    output["nedb"] = {}
+    let openRequest = window.indexedDB.open("NeDB")
+    openRequest.onsuccess = () => {
+        let db = openRequest.result
+        let objectStore = db.transaction("nedbdata").objectStore("nedbdata")
+        let cursorRequest = objectStore.openCursor()
+        cursorRequest.onsuccess = () => {
+            let cursor = cursorRequest.result
+            if (cursor) {
+                output["nedb"][cursor.key] = cursor.value
+                cursor.continue()
+            } else {
+                fs.writeFile(path, JSON.stringify(output), (err) => {
+                    if (err) remote.dialog.showErrorBox(intl.get("settings.writeError"), String(err))
+                })
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/scripts/utils.ts b/src/scripts/utils.ts
index 455150c..2694a56 100644
--- a/src/scripts/utils.ts
+++ b/src/scripts/utils.ts
@@ -69,3 +69,19 @@ export const cutText = (s: string, length: number) => {
 }
 
 export const googleSearch = (text: string) => openExternal("https://www.google.com/search?q=" + encodeURIComponent(text))
+
+export function mergeSortedArrays<T>(a: T[], b: T[], cmp: ((x: T, y: T) => number)): T[] {
+    let merged = new Array<T>()
+    let i = 0
+    let j = 0
+    while (i < a.length && j < b.length) {
+        if (cmp(a[i], b[j]) <= 0) {
+            merged.push(a[i++])
+        } else {
+            merged.push(b[j++])
+        }
+    }
+    while (i < a.length) merged.push(a[i++])
+    while (j < b.length) merged.push(b[j++])
+    return merged
+}
\ No newline at end of file