Pale Moon - Your browser, Your way

Known issues in the current version

Development notes

The Pale Moon browser, at any point in time, may have a number of known issues. These known issues will usually be addressed in the next release of the browser, or it may be something that people have noticed and are mentioned here because they are "by design", i.e.: issues people have asked about, are known, and are this way on purpose.
For each issue, check the status for intended action to be taken in development (if any) and intended timeline (if applicable).

Known issues in the current version:
  1. Android: using VPN connections may not work
    If you are using a VPN connection on Android 5 (Lollipop), Pale Moon may not be able to resolve host names, leading to connectivity failures. This is caused by a known problem in the underlying Fennec code that caters to much older versions of Android and relies on functions that have been removed in Android 5.*
    Status: [Fixed]
    Workarounds: Use local (on-device) DNS resolution with a DNS resolver, use a different browser for VPN use, or downgrade to Android 4.*
    Timeline: Fixed in 25.4
  2. Subpixel rendering for fonts is sub-optimal in some elements
    Some elements of the browser (e.g. tooltips and some web page elements) use suboptimal font rendering. This is caused by a deep-rooted issue in the gecko graphics rendering back-end affecting all gecko-based browsers, that requires time to research.
    Effects are only aesthetic in nature and non-breaking.
    Status: [Research]
    Workaround: disable hardware acceleration
  3. A number of Firefox extensions are missing browser interface elements
    This is caused by Pale Moon's GUID change and the presence of targeted code or overlays in the extension.
    More information: FAQ
    Status: Caused by extension restrictions
    Fix: Contact the extension author and have them update their extension to include support for Pale Moon
    Workaround/Fix: Check for an updated version for Pale Moon 25+
    Workaround (advanced): manually edit chrome.manifest inside the extension archive (see forum)

Known issues in all versions:

  1. The browser creates directories under %APPDATA%\Mozilla, specifically Mozilla\Extensions
    These directories are related to the underlying Mozilla extension code (Pale Moon is a Mozilla-based browser) and stores extension IDs there. This issue is completely harmless and non-breaking; in fact, having (all) Mozilla-based applications use this one central location for extension IDs is desired.
    Status: [By Design]

Known issues in previous versions

Because issues in previous versions may still apply to what people are running, here is a recap of previous, still recent versions that have been fixed, and potential workarounds:

  • Some Single-Sign-On (SSO) setups don't work
    Because of a security vulnerability with authentication redirection (cookie injection) through proxies (CVE-2014-8639 MFSA2015-04), Pale Moon currently does not allow auth cookies to pass through or be modified by proxies. This may make some SSO setups fail to authenticate to individual services (usually on corporate intranetworks that employ proxies) and as a result the user is asked to provide login details.
    Status: [Fixed], following the relevant Mozilla bugs.
    The vulnerability patch was adapted to allow for cookies to be stored by authenticating proxies, but not on proxy connection failures, greatly reducing the available scenarios for this already difficult to practically exploit session fixation vulnerability. It should be sufficiently mitigated this way while not being in the way of legitimate cookie injection requests. In environments where this is a concern, the session policies should be revised or implemented in a different way.
    Workaround: Avoid using proxies for SSO.
  • Add-on update checks don't work
    This is caused by a hidden, undocumented feature in the Mozilla code that requires a very strict check on the certificate presented by the add-ons server.
    Status: [Fixed]
    Workaround: Create a new boolean preference called extensions.update.requireBuiltInCerts and set it to false
    Timeline: Fixed in 25.0.2
  • Some parts of Devtools don't work
    This is caused by the rather unexpected in-app useragent sniffing that the devtools do (yes, seriously!)
    Without Firefox/* in the UserAgent string, the JavaScript debugger and Style Editor (and possibly a few other functions) don't work properly or at all.
    Status: [Fixed]
    Workaround: Set general.useragent.compatMode.firefox to true
    Timeline: Fixed in 25.0.2
  1. Some jetpack add-ons that should work refuse to work properly
    This is caused by some add-on SDK files missing the new Pale Moon ID in them.
    Status: [Fixed]
    Timeline: Fixed in 25.0.1
  1. Rendered text color may become the wrong color or white when scrolling
    In some situations, colored fonts may become the wrong color or white when scrolling and hardware acceleration is enabled in the browser.
    Workaround: set layers.force-active to true in about:config
    Status: [Fixed]
    Timeline: Fixed in 24.7.1
  2. Google Maps on displays a non-functional preview of the "new" maps.
    This is caused by interpretation of the custom user agent in Pale Moon for the domain.
    Workaround: see
    Status: [Fixed]
    Timeline: Fixed in 24.7.1
  1. Domain highlighting sometimes works and sometimes doesn't
    This is caused by a conflict with domain highlighting and the code to have status indicators in the address bar.
    Workaround: Disable domain highlighting in the status bar options
    Status: [Fixed]
    Timeline: Fixed in 24.7.0
  1. After upgrading from 24.5 or before, the browser may crash on startup
    On systems where people have previously changed the advanced preference "" or "", 24.6.0/24.6.1 may crash or immediately close upon startup.
    This is caused by a multi-tiered problem in graphics engine selection, which sometimes causes an invalid or incompatible choice to be made by the browser.
    Workaround: Start the browser with SHIFT held down, and in the safe mode dialog box, click "Reset all user preferences to Pale Moon defaults" and then click "Make changes and restart"
    Workaround 2: Start the browser in safe mode (Start with SHIFT, then click "Continue in Safe Mode"), and manually reset all gfx.* preferences in about:config
    Workaround 3: Start the browser in safe mode, and set "gfx.direct2d.disabled" to "true" in about:config
    Workaround 4: Start the browser in safe mode and perform a browser reset from the Help -> Troubleshooting information page.
    Status: [Fixed]
    Timeline: Fixed in 24.6.2
  1. On certain systems, rendering of text and graphics may become "pixelated"
    If you are using Windows 7 SP1 with the (Feb 28th 2013) Windows Platform Update (KB 2670838), or potentially also if you are using Windows 8/8.1, and your system is equipped with a certain legacy ATI/AMD Radeon (specifically an HD3000 or HD4000 series) graphics processor, you may encounter issues with rendering text and graphics in page content, similar to:

    This is caused by the combination of OS, the Platform Update which makes changes to DirectX, and the graphics hardware/drivers in your system. Unfortunately, it's not clear who exactly is to blame, as people keep pointing fingers to others (Microsoft, AMD, Mozilla). Note that the update may also have been installed as a prerequisite for using MSIE 10/11.
    Of note: Later versions of Pale Moon are less likely to display this error than Firefox, but it may still occur.
    See - TL;DR: uninstall KB2670838 or disable azure for content.
    Fixed in 24.6.0.
  2. On some Windows 8/8.1 systems, the browser regularly crashes
    This is caused by a problem in the Gecko rendering engine on the newer version of Direct2D (introduced in Windows 8, 8.1 and through the Platform Update of Windows 7) when hardware acceleration is used.
    Status: [Fixed]
    Timeline: Fixed in 24.6.0.
  1. On some sites, the plugin notification icon may incorrectly show or provide a blank doorhanger
    This is caused by page content removing document nodes and confusing the plugin indicator code. As a result, you will see the following when clicking the plugin indicator:
    Workaround: None
    Status: [Fixed]
    Timeline: Fixed in 24.5.
  1. The download manager panel may pop up in the far bottom-left
    On some installations, the download manager panel may possibly pop up on the bottom left of the browser instead of where the download manager button is. This is caused by a small issue in the default set of controls in the v24.4.0 updated status bar code, confusing the panel by having 2 places to "hang" the panel from.
    I will be fixing this by removing the status bar download control from the "default" set of controls (like in previous versions).
    Workaround: Open the customization window (right-click a toolbar button and select Customize... from the menu) and remove the download manager control you don't intend to use (either the button in the main navigation bar or the control in the status bar) by dragging it from the browser window to the customization window.
    Status: [Fixed]
    Timeline: Fixed in 24.4.2.
  1. Trying to open up the download manager from the download status control doesn't work
    Trying to open up the download manager (either panel or classic window) by clicking on the status bar control for downloads does nothing. This is caused by a small issue in the newly updated status bar code in 24.4.0.
    Status: [Fixed]
    Timeline: Fixed in 24.4.1
  1. When using the classic downloads window, downloads in private windows are not shown
    If you use the classic downloads window and open a Private Browsing (PB) window, there is no easy way to see which downloads are done in the PB window. When checking the downloads, it will open up the (non-PB) classic downloads window which does not have downloads listed from the PB session.
    This is caused by PB windows being implemented after Mozilla moved to the panel-based downloads manager, and there is no check in the classic downloads window if it is called from a PB window or regular window.
    Workaround: In the PB window, open a new tab and type about:downloads in the address bar
    Status: [Fixed]
    Timeline: Fixed in 24.3.0
  2. Geolocation doesn't work in Pale Moon
    This is caused by the Firefox standard geolocation provider (Google Inc.) now requiring an API key to request geolocation coordinates. Only official Mozilla Firefox builds of the code will work.
    Pale Moon will be switching provider to address this issue.
    Workaround: none.
    Status: [Fixed]
    Timeline: Fixed in 24.3.0
  3. The "More information" link for blocked add-ons doesn't work
    Workaround: See
    Status: [Fixed]
    Timeline: Fixed in 24.3.0
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