SeaMonkey 2.1 Beta 2

These release notes describe system requirements, installation instructions, and known issues for SeaMonkey 2.1 Beta 2. These notes are updated when we receive feedback, so please check back for new information.

Warning! The SeaMonkey version descibed on this page is an outdated testing-only preview of the next generation of our Internet suite. Please test a newer preview version instead of this one.
For daily use, we strongly advise you to download the current stable release instead.

What's New in SeaMonkey 2.1 Beta 2

SeaMonkey 2.1 Beta 2 contains the following major changes relative to SeaMonkey 2.1 Beta 1:

  • The new Data Manager is opened instead of the previous separate management windows.
  • Page zoom is being remembered on a site-specific basis now.
  • WebSockets have been disabled for security reasons.
  • Lightweight themes (Personas) support for the Address Book, Composer, and MailNews windows.
  • Deferred Session Restore.
  • The browser tab bar is now scrollable (also using the mouse wheel) to cope with tab overflow. Includes an "All Tabs" navigation button to quickly list all open tabs.
  • News messages can now be deleted from local storage.
  • Website search fields now feature a "Add a Keyword for this Search" context menu entry.
  • In some places where previously a notification bar appeared (like remembering log-in passwords or after installing an extension), SeaMonkey now shows a "doorhanger" below the location bar.
  • SeaMonkey now uses Omnijar which results in fewer installed files, less fragmentation and better startup time.
  • Sync (f.k.a. Weave) is now included directly in SeaMonkey. Sync allows you to keep your browsing history, passwords, bookmarks, preferences and tabs in sync across different devices (computers) in a secure way.
  • Mac changes: PPC support was dropped, 64-bit support for 10.6 "Snow Leopard" was added.
  • The new DoNotTrack HTTP header can be configured in Preferences, Privacy & Security
  • WebGL and D3D are now enabled where supported (hardware acceleration, see about:support)
  • Improved OpenType support
  • HTML5 Forms API support
  • Various Add-on Manager improvements
  • Faster bookmarking and startup performance (due to Places changes)
  • Flash on Mac OS X improvements
  • Memory usage improvements

See the SeaMonkey Trunk Tracker blog for more details about the changes between those pre-releases.
The changes page lists an overview of new features and fixes relative to our last stable release, SeaMonkey 2.0.12.


The SeaMonkey project provides official versions of SeaMonkey 2.1 Beta 2 for Windows, Linux, and Mac OS X in US English and experimental language packs for a small variety of other languages. Community volunteers are also contributing builds for other platforms. You can download SeaMonkey 2.1 Beta 2 here.

System Requirements, Installation and Uninstallation

Before installing, make sure your computer meets the system requirements. SeaMonkey 2.1 Beta 2 will offer to migrate your data from SeaMonkey 1.x or Mozilla 1.x at the first start after installation. You can find more details about installation, profile data and uninstallation in our install and uninstall document.
As this is a developer preview, install it in a different location and use a different profile if you want to make sure it doesn't affect your existing SeaMonkey 2.0 installation.

Extensions and Themes

Extensions installed under SeaMonkey 1.x are not migrated to SeaMonkey 2, and may not be compatible for reinstalling in this version due to major changes in our architecture. Please report any issues to the maintainer of the extension. Extensions and Themes for SeaMonkey 2.1 Beta 2 can be installed from the SeaMonkey Add-Ons website or the "Get Add-Ons" section in the Add-Ons manager.

Known Issues

This list covers some of the known problems with SeaMonkey 2.1 Beta 2. Please read this before reporting any new bugs.
  • ChatZilla does not display anything in the message window (bug 605001).
  • Select Element by Click doesn't flash the element in DOM Inspector on Windows (bug 594299).
  • NS_ERROR_NOT_IMPLEMENTED when opening Venkman (JavaScript Debugger) (bug 614557).
  • Data loss warning: If you use a profile with this beta or any later version and then try to go back to SeaMonkey 2.0, SeaMonkey will rename your history file to places.sqlite.corrupt and create a new places.sqlite file, effectively resetting your browsing history. This is because the internal format changed and the upgrade process only works in one direction.
  • SeaMonkey Sync UI does not fully match Firefox Sync UI yet, but both are using the same back-end. To use a Sync account with multiple devices you need to make sure all of them use the latest version of Sync (i.e. always use the latest beta of SeaMonkey 2.1 or Firefox 4, desktop and mobile) (bug 615950).
  • After installing the latest Firebug 1.7 pre-release and restarting the application, the Navigation Toolbar may be broken (issue 4086).
  • Mac:
    • When hardware acceleration is off, background colors in the UI (toolbar, status bar etc.) might not update correctly when you switch focus from/to a window. Users running Macs with certain older hardware (e.g. Intel GMA 950) will experience this even if they haven't turned off hardware acceleration in Preferences (Appearance/Content) (bug 626096).
    • The 32-bit Microsoft Silverlight plugin fails to load when using a 64-bit version of SeaMonkey on Mac OS X 10.6. Sites that depend on the plugin (such as Netflix) will fail to work. You will need to restart in 32-bit mode: Close SeaMonkey, go to the Applications folder, right-click the SeaMonkey application icon, choose "Get Info", select "Open in 32-bit mode" (bug 598406).
  • Linux:
    • The video control buttons may not work when viewing QuickTime videos with libtotem (bug 625036).
    • Users compiling from source might need a newer gcc and libstdc++ as the build requirements have changed (bug 578880).


  • Some anti-virus software keeps detecting our installers as containing a "Trojan" or "Downloader". This is a false positive and is some wrong detection mechanism in the anti-virus software. The code in question is actually from 7-Zip and decompresses the installer so that its contents can run and install SeaMonkey. That technology is widely used and probably can be used to compress bad as well as good software, but the 7-Zip code itself is perfectly safe. Mozilla scans all our files routinely when putting them on the FTP server and we assure you that our installers are as clean as the official Firefox downloads that are scanned by the same mechanisms.
  • Poorly designed or incompatible extensions can cause problems with SeaMonkey, including make it crash, slow down page display, etc. If you encounter strange problems relating to parts of SeaMonkey no longer working, the browser not starting, windows with strange or distorted appearance, degraded performance, etc, you may be suffering from Extension or Theme trouble. Restart SeaMonkey in Safe Mode. On Windows, start using the "Safe Mode" shortcut created in your Start menu or by running seamonkey.exe -safe-mode. On Linux, start with ./seamonkey -safe-mode and on Mac OS X, run:

    cd /Applications/
    ./seamonkey-bin -safe-mode

    When started in Safe Mode all extensions are disabled and the Default theme is used. Disable the Extension/Theme that is causing trouble and then start normally.
  • If you uninstall an extension that is installed with your user profile (i.e. you installed it from a Web page) and then wish to install it for all user profiles using the -install-global-extension command line flag, you must restart SeaMonkey once to cleanse the profile extensions datasource of traces of that extension before installing with the switch. If you do not do this you may end up with a jammed entry in the Extensions list and will be unable to install the extension globally.
  • If you encounter strange problems relating to bookmarks, downloads, window placement, toolbars, history, or other settings, it is recommended that you try creating a new profile and attempting to reproduce the problem before filing bugs. Create a new profile by running SeaMonkey with the -P command line argument, choose the "Manage Profiles" button and then choose "Create Profile...". Migrate your settings files (Bookmarks, Saved Passwords, etc) over one by one, checking each time to see if the problems resurface. If you do find a particular profile data file is causing a problem, file a bug and attach the file.

Frequently Asked Questions

What can I do to help?
We need help from developers and the testing community to provide as much feedback as possible to make SeaMonkey even better. Please read these notes and the bug filing instructions before reporting any bugs to Bugzilla. You can also give us your feedback through this feedback form.
Why haven't you responded to the mail I sent you?
Use the newsgroup. The SeaMonkey team reads it regularly, and your email may have gotten lost.
Where can I get extensions and themes (add-ons)?
Extensions and Themes can be downloaded from SeaMonkey Add-ons.
Who makes SeaMonkey?
Lots of people. See Help->About SeaMonkey, contributors for a list of some of the people who have contributed to Mozilla and SeaMonkey.
Where's the SeaMonkey 2.1 Beta 2 source code?
A tarball of the SeaMonkey 2.1 Beta 2 source code is available at the download page. The latest development code can be obtained from the source repository. SeaMonkey-specific source is in the "suite" directory. Please follow the build instructions.

Other Resources and Links

The following resources contain useful information about SeaMonkey 2.1 Beta 2: