Firefox web browser does not start. No Firefox window opens. How do I fix it in MINUTES?

Amazon If you use Firefox on Windows 7, one day you may find that Firefox suddenly does not start, meaning when you click on the Firefox icon, no window opens. It happened to me and I managed to fix this issue by following the following solutions.

Read on to see how I got Firefox to start again.

The cause

The cause of the Firefox-not-starting issue could be due to virus or malware, or it could be because your system is running in an inconsistent state, where running one program causes the other program to not run properly. In any case, the following solutions will help you fix this problem.

Solution 1

Restart your computer and try running Firefox again. Rebooting your PC is the common solution to many Windows problems, and it has a good chance of working. If it does not work for you, read on.

Solution 2

Do a clean, full re-installation of Firefox. But make sure you follow these steps to ensure a proper re-installation without losing your data.

Step 1

If you don't want to keep any browser data such as bookmarks or Greasemonkey scripts, then delete the folder

C:\Users\<your user name>\AppData\Roaming\Mozilla

If you want to keep your old data, rename the folder

C:\Users\<your user name>\AppData\Roaming\Mozilla

C:\Users\<your user name>\AppData\Roaming\Mozilla-old

Step 2

Uninstall Firefox by going to Control Panel -> Uninstall a program and selecting Firefox to uninstall.

Step 3

Delete the folder

C:\Program Files (x86)\Mozilla Firefox

C:\Program Files\Mozilla Firefox

depending on your installation.

Step 4

Download and install the offline version of Firefox at https://www.mozilla.org/en-US/firefox/all/. My version is 37.0.2 at the time of the writing.

Step 5 - follow this step only if you want to restore old data

Recover the old data in your new installation of Firefox. For example, to recover bookmarks, click Control Shift B to open the Library window. Then go to Import and Backup -> Restore -> Choose File... and select the latest .jsonlz4 file in C:\Users\<your user name>\AppData\Roaming\Mozilla-old\Firefox\Profiles\e2jqfdpg.default\bookmarkbackups.

e2jqfdpg.default may be named differently on your system.

To recover Greasemonkey scripts, copy the folder

C:\Users\<your user name>\AppData\Roaming\Mozilla-old\Firefox\Profiles\e2jqfdpg.default\gm_scripts

C:\Users\<your user name>\AppData\Roaming\Mozilla\Firefox\Profiles\juvjdtsu.default

Then install Greasemonkey add-on (My version is 3.1) in Firefox. Restart Firefox.

juvjdtsu.default may be named differently on your system.

Eventually, I found out that the real culprit was C:\Users\<your user name>\AppData\Roaming\Mozilla. That's why You must delete or rename the folder before you install Firefox again.

Questions? Let me know!