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Firefox crashes

  • 6 replies
  • 1 has this problem
  • 117 views
  • Last reply by jbagent7

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Windows.old file, leftover from upgrade to Windows 7, was removed via Disk Cleanup. Now no browser will start. Error message "cannot read nss3.dll file."

Windows.old file, leftover from upgrade to Windows 7, was removed via Disk Cleanup. Now no browser will start. Error message "cannot read nss3.dll file."

Chosen solution

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) to see if that helps.

Can you use another computer to download the full Firefox installer and possibly some malware scanning software?

Try this:

You can copy the file to the desktop and start the installation with a double-click on the desktop icon.

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Greeting jbagent7,

What Is Nss3.dll?

Nss3.dll is a type of DLL file associated with Firefox developed by Mozilla Foundation for the Windows Operating System. The latest known version of Nss3.dll is 27, which was produced for Windows. This DLL file carries a popularity rating of 1 stars and a security rating of "UNKNOWN".

What Are DLL Files?

DLL ("dynamic link library") files such as nss3.dll are small programs, similar to EXE ("executable") files, which allow multiple software programs to share the same functionality (eg. printing).


Why Do I Have DLL Errors?

Because they are shared files, DLL files exist outside of the software application itself. Although this provides many benefits for software developers, this separation also provides an opportunity for problems to occur.

Quite simply, if Windows cannot properly load your nss3.dll file, you will encounter an error message. Please see "Causes of nss3.dll Errors" below for more information.

When Do DLL Errors Occur?

DLL errors, such as those associated with nss3.dll, most often occur during computer startup, program startup, or while trying to use a specific function in your program (eg. printing).


Kindly Check this link: http://www.solvusoft.com/en/files/missing-not-found-error/dll/windows/mozilla-foundation/firefox/nss3-dll/

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Do a clean reinstall and delete the Firefox program folder before (re)installing a fresh copy of the current Firefox release.

If possible uninstall your current Firefox version to cleanup the Windows registry and settings in security software.

  • Do NOT remove "personal data" when you uninstall your current Firefox version, because this will remove all profile folders and you lose personal data like bookmarks and passwords including data in profiles created by other Firefox versions.

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

  • (32 bit Windows) "C:\Program Files\Mozilla Firefox\"
  • (64 bit Windows) "C:\Program Files (x86)\Mozilla Firefox\"

Your personal data like bookmarks is stored in the Firefox profile folder, so you won't lose personal data when you uninstall and (re)install or update Firefox, but make sure NOT to remove personal data when you uninstall Firefox as that will remove all Firefox profile folders and you lose your personal data.

If you keep having problems then create a new profile.


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Cannot communicate with internet, as neither IE nor Firefox can be opened. Tried reloading Windows 7 from my upgrade CD, but failed because "the version in your computer is newer than that on this CD."

Email does work, so there is a good path to the web. Just no browser.

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Chosen Solution

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) to see if that helps.

Can you use another computer to download the full Firefox installer and possibly some malware scanning software?

Try this:

You can copy the file to the desktop and start the installation with a double-click on the desktop icon.

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Perform a System File Check to fix corrupted system files Win 7, 8, 10, Vista: https://support.microsoft.com/en-us/kb/929833

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Obtained Firefox installer using another computer, copied it to desktop of failing computer, and installed fresh copy of Firefox. Problem solved. Thanks for the help!