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Creating a Cookie Log

Creating a cookie log is often necessary to troubleshoot problems with Firefox's cookie handling.  If you are reading this, you have probably been directed here from a bug report.  Please follow the instructions below to run Firefox with cookie logging enabled.

Enabling Cookie Logging

Windows

Open a command prompt (this is under Programs or Programs/Accessories in normal installations of Windows).

  1. Change to your Firefox directory (usually C:\Program Files\Mozilla Firefox)
  2. Type "set NSPR_LOG_FILE=C:\temp\cookies-log.txt", enter
  3. Type "set NSPR_LOG_MODULES=cookie:4" and press Enter
  4. Run Firefox by typing "firefox.exe" and pressing Enter.

Linux

Start a command shell (these instructions are for bash, if you use something else, you probably know how to modify these instructions already).

  1. Change to the installation directory for Firefox.
  2. Type "export NSPR_LOG_FILE=~/cookies-log.txt" and press Enter.
  3. Type "export NSPR_LOG_MODULES=cookie:4" and press Enter.
  4. Run Firefox by typing "./firefox" and pressing Enter

Mac OS X

Open Terminal.app, which is located in the /Applications/Utilities folder (these instructions are for bash, the default shell in Mac OS X 10.3 and higher; if you use something else, you probably know how to modify these instructions already).

  1. Change to the installation directory for Firefox, e.g. type "cd /Applications/Firefox.app/Contents/MacOS" and press Return.
  2. Type "export NSPR_LOG_FILE=~/Desktop/cookies-log.txt" and press Return.
  3. Type "export NSPR_LOG_MODULES=cookie:4" and press Retrun.
  4. Run Firefox by typing "./firefox-bin" and pressing Return (note that Firefox will launch behind windows for other applications).

Creating the Log

Now that you have Firefox running with logging enabled, please try to replicate the bug using the steps to reproduce from the bug report.  Once you have replicated the bug, shut down Firefox.  Close out of the command prompt/shell/Terminal, and then launch Firefox normally.  Finally, attach the cookies-log.txt to the bug where it was requested (by clicking on Create New Attachment).  It should be in C:\temp on Windows, your home directory on Linux, or the Desktop on Mac OS X.

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