This is kind of an annoying error message comes from Mozilla Firefox when you start Mozilla Firefox or when you browse the internet for a while.
How to fix “firefox.exe has encountered a problem and needs to close. We are sorry for the inconvenience.” error?
Most of the time this error comes due to newly add-on installation which is not installed from Mozilla Firefox add-ons and also due to not updating Firefox properly. If you just install a new software which installs a new add-on to Mozilla Firefox.
Go to Tools and Add-ons on Mozilla Firefox.
Disable the new add-on which is installed by new software installation.
Restart the Mozilla Firefox and check you still get the same error.
If still the error comes go to Control Panel –> Add or Remove Programs uninstall Mozilla Firefox.
Download newest Mozilla Firefox and Install.
Open Mozilla Firefox. Error will not appear again.