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ERROR Registering: C:\Program Files (x86)\Mozilla Firefox\AccessibleMarshal.dll and failure to install

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  • Last reply by cor-el

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I downloaded and extracted the latest ESR file (Version 10.0.7) this morning. Running SETUP.EXE with no command line switches fails to install Firefox. Ths installation log indicates that the installation has taken 1 second to complete execution. In the Installation log I see the following:


DLL Registration


 ** ERROR Registering: C:\Program Files (x86)\Mozilla Firefox\AccessibleMarshal.dll **

In the C:\Program Files (x86)\Mozilla Firefox folder there is an uninstall folder as well as an install.log file. No other files or folders exist. Mozilla Firefox does appear in the Programs and Features but shows an icon associated with an unknown application.

I am logged in with a low-rights account but running the SETUP.EXE executable from an elevated command prompt. This should be sufficient to elevate the DLL registration.

Running on Windows 7 SP1 with all applicable updates. I've noticed several other people that have experienced this issue but nobody has a solution.

Thanks in advance for any help!

Chosen solution

Do a clean reinstall and delete the Firefox program folder before reinstalling a fresh copy of Firefox.

Download a fresh Firefox copy and save the file to the desktop.

Uninstall your current Firefox version, if possible, to cleanup the Windows registry and settings in security software.

  • Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you will also lose your personal data like bookmarks and passwords from profiles of other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

Your bookmarks and other profile data are stored in the Firefox Profile Folder and won't be affected by an uninstall and (re)install, but make sure that "remove personal data" is NOT selected when you uninstall Firefox.


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Chosen Solution

Do a clean reinstall and delete the Firefox program folder before reinstalling a fresh copy of Firefox.

Download a fresh Firefox copy and save the file to the desktop.

Uninstall your current Firefox version, if possible, to cleanup the Windows registry and settings in security software.

  • Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you will also lose your personal data like bookmarks and passwords from profiles of other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

Your bookmarks and other profile data are stored in the Firefox Profile Folder and won't be affected by an uninstall and (re)install, but make sure that "remove personal data" is NOT selected when you uninstall Firefox.