當 Firefox 當掉時，他可能會停止回應你的點擊，而且看起來什麼都不做。而且一個「無回應」標籤會顯示在標題列，且當滑鼠指向 Firefox 視窗上時，會顯示成一個旋轉的沙漏。這篇文章將會根據實際的情形，提供你一些解決方案。

• If Firefox uses a lot of computer resources, see the solutions proposed in Firefox 耗用過多 CPU 資源 - 如何解決 and Firefox 使用太多的記憶體 - 如何修正.
• If you get a "Warning: Unresponsive script" prompt, see 指令碼沒有反應的警告 – 這代表什麼與如何解決.
• If Firefox closes unexpectedly, see Firefox 發生錯誤 - 疑難排解，避免再次發生錯誤並取得協助.

To resolve hanging problems not specifically mentioned in this article, or if the suggested solutions do not solve the problem, see 解決 Firefox 的疑難雜症.

Firefox hangs at random times

If Firefox seems to hang randomly and not after a specific action (for example, downloading a file or quitting Firefox), try the solutions in this section.

Create a new places database

If hangs are periodic, it may be caused by a corrupted places database. To create a new places database, do the following:

1. 模板「ProfileFolder」不存在，或是沒有通過審核的版本。
2. 點擊 Firefox 選單，然後點擊結束。點擊畫面頂端的 Firefox 選單，然後選擇離開 Firefox。點擊 Firefox 選單，然後選擇離開。 Wait until Firefox has completely quit.
3. In the Firefox profile folder, find and rename the files places.sqlite and places.sqlite-journal (if it exists).
   • To rename a file, right-click on it and select rename from the menuclick on it once to select it and then click a second time on the file name to make it editable. Then add .old to the end of its name.
4. Finally, reopen Firefox.
   • When Firefox reopens it will create a new places database. Your browsing history will be lost but Firefox will automatically import your bookmarks from the most recent backup file.

Turn off hardware acceleration

With some graphics card and graphics driver setups, Firefox may hang when using hardware acceleration. You can try turning off hardware acceleration to see if it fixes the problem.

1. 在畫面頂端的選單列點擊 Firefox 並選擇 設定（在舊版 macOS 上選擇 偏好設定）。點擊選單按鈕 後，選擇 設定。
2. Select the Advanced panel and the General tab.
3. Uncheck Use hardware acceleration when available.
4. 點擊 Firefox 選單，然後點擊結束。點擊畫面頂端的 Firefox 選單，然後選擇離開 Firefox。點擊 Firefox 選單，然後選擇離開。
5. Start Firefox the way you normally do.

If the problem is no longer happening, then hardware acceleration was likely the cause. You can try updating your graphics drivers to see if that fixes it or simply run without hardware acceleration.

Troubleshoot your plugins

Sites that use plugins such as Java, Adobe Reader, or Flash can cause Firefox to hang. For information on troubleshooting plugins and on determining whether a plugin is causing your problem, see the 外掛程式問題排解 article.

Delete duplicated Session Restore files

Firefox may be slow to respond or hang if multiple copies of its Session Restore file have been created:

1. 開啟你的個人設定資料夾:

   • 點擊選單按鈕，點擊 說明並選擇更多疑難排解資訊。在 說明選單點選更多疑難排解資訊。疑難排解資訊將會開啟。
   • 在應用程式一般資訊段落下方，可找到設定檔資料夾設定檔目錄，點擊開啟資料夾在 Finder 顯示開啟目錄。將開啟包含您的設定檔目錄。將開啟您的設定檔資料夾。
   註： 若點擊開啟資料夾之後，Firefox 顯示錯誤，或如果您無法開啟或使用 Firefox，請依照下列文章的指示操作：在不開啟 Firefox 的情況下尋找設定檔。

2. 點擊 Firefox 選單，然後點擊結束。點擊畫面頂端的 Firefox 選單，然後選擇離開 Firefox。點擊 Firefox 選單，然後選擇離開。
3. Locate and delete the sessionstore.js file and any copies, such as sessionstore-1.js, sessionstore-2.js.

Change the PAC implementation

If you're using a proxy auto-config file (PAC), Firefox may hang when you attempt to load sites that don't exist or that you haven't opened recently. To determine if you use an automatic proxy configuration file:

1. 在畫面頂端的選單列點擊 Firefox 並選擇 設定（在舊版 macOS 上選擇 偏好設定）。點擊選單按鈕 後，選擇 設定。
2. Click the Advanced icon.
3. Click the Network tab.
4. Click Settings. The Connection Settings dialog appears.
5. If Automatic proxy configuration URL is selected, you are using an automatic proxy configuration file. Do not disable this setting, which will prevent you from accessing the Internet. Instead, provide this workaround to your network administrator.
6. Click Cancel.

Firefox hangs while playing Flash videos

See Playing Flash videos makes Firefox hang.

Firefox hangs after using it for a long time

Update Firefox

The latest Firefox versions includes improvements in memory usage, especially during long sessions. Update Firefox to the latest version.

Restart Firefox

Firefox may hang if left open for long periods of time. To fix the issue, restart Firefox.

If you regularly leave Firefox open so that you return to where you left off, you may want to use Firefox's Session Restore feature. For more information, see Configuring session restore.

Firefox hangs while loading the first window

Speed up Session Restore

If you have many tabs to restore, Firefox may hang while loading those sites. Make sure to check Don't load tabs until selected in the Tabs panel of the OptionsPreferences windowGeneral panel of the OptionsPreferences window so that only the last selected tab is loaded at startup. Try to use Tab Groups so that only websites in the visible tab group load first.

Firefox hangs when downloading files or saving images

If Firefox hangs when you attempt to download a file or save an image, try these solutions:

Clear download history

Firefox may hang when downloading files if your download history has grown too large. To clear the download history:

1. At the top of the Firefox window, click on the Firefox button (Tools menu in Windows XP), and then click DownloadsOn the menu bar, click on the Tools menu, and then click DownloadsAt the top of the Firefox window, click on the Tools menu, and then click Downloads. The Downloads window will open.
2. Click Clear List. The download history is cleared.
3. Download some sample files to see if the hanging has stopped.

Choose a different download folder

Firefox may hang if the last download folder location (e.g. a shared volume or USB drive) is no longer available. To fix this:

1. 在畫面頂端的選單列點擊 Firefox 並選擇 設定（在舊版 macOS 上選擇 偏好設定）。點擊選單按鈕 後，選擇 設定。
2. Select the General panel.
3. In the Downloads pane, select Save files to and click the Browse button.
4. In the Browse For Folder window, choose a new folder location.
5. 關閉設定頁面。您做的任何修改都會自動被儲存。

See if you are now able to download files or save images. If this works, you can go back to your Firefox settings, if you wish, and select Always ask me where to save my files.

Disable virus scan in Firefox preferences

With some antivirus programs, the virus scan that Firefox starts after files are downloaded may cause Firefox to hang. You can disable virus scanning with the following steps (this will not disable your antivirus program):

1. 在 網址列 輸入 about:config 然後按下 EnterReturn。
   可能會出現警告頁面，點擊我發誓，我一定會小心的！接受風險並繼續，接著就會前往 about:config 頁面。
2. Locate the browser.download.manager.scanWhenDone preference and double click it to change the value to false.

Firefox hangs when you quit it

Sometimes when you close Firefox, it may stop responding and remain in memory, even though no Firefox windows are open. This can prevent Firefox from working properly the next time you open it or you may see a "Close Firefox" dialog box with the message, Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.. You must then end all Firefox processes or restart the computer before you can reopen Firefox (see 如何解決? "FIrefox正在運作但無法回應指令" for other causes and solutions).

Close Firefox completely

1. 點擊 Firefox 選單，然後點擊結束。點擊畫面頂端的 Firefox 選單，然後選擇離開 Firefox。點擊 Firefox 選單，然後選擇離開。
2. Close any remaining dialog boxes or secondary windows such as the Downloads window.

If Firefox processes that remain in memory at exit are a recurring problem, try the following solutions.

Troubleshoot your extensions

A problematic extension can cause the problem, which can be resolved by disabling or uninstalling the extension. For information on diagnosing and fixing problems caused by faulty extensions, see the 解決擴充套件、佈景主題以及硬體加速造成的 Firefox 常見問題 article.

Update or disable the Java plugin

Sometimes Java applets can cause the Firefox process to persist after exit. Try updating Java to the latest version by going to Mozilla's plugin check page or, if you don't need the Java plugin, you can disable it from the Plugins panel of the Firefox Add-ons Manager. For more information, see 使用 Java 外掛程式檢視網站上的互動內容.

Based on information from Firefox hangs (mozillaZine KB)