What is "safe mode"??????????????????

In windows safe mode is a startup option where the OS loads with minimal
drivers and backround programs. Its used for system diagnosis. If a
system has problems and works ok in safe mode that indicates the problem
has to do with third party software. If it fails to boot, its an
indication that the system has problems. Its a nice diagnostic tool. I'm
not aware of anything similar in Linux, but if there is something like
this, I would love to learn about it.

I'd heard of safe mode with regard to windows, but had no idea how that
might apply to linux. The closest thing I can think of in linux is
single user mode, which is used for filesystem repairs and other
maintenance.

sudo telinit -s......................

He did so at the bottom.

(Can we now see why its very helpful for everyone to post in the same
place? Just asking)

Yes, that is a way to put a unix box in single user mode, but it
wouldn't be useful for testing firefox. The safe mode of firefox is
something a bit different.

Maybe we need to know what the REAL question is? ffox in safe-mode
basically runs the default, out-of-the-box, configuration. If there is
a bad add-on I guess that might help find it. So would a fresh install.

Currently I have 20 add-ons. Not all are enabled. I know that some
people run a lot more than that. I can see problems cropping up,
especially after add on updates, that people may not notice for days or
weeks. It would be a bit of a pain to disable all add-ons and later
enable then again, remembering which were initially disabled.
Acknowledging the fact that they may well have to be enabled one or a
few at a time to troubleshoot. but the possibility to limit the problem
directly to the Firefox program and not something in the operating
system is a very handy tool.

now, how do i make it work? says invalid option when i try.

www.makeuseof.com/.../

ok - so it's apparently a startup option you can pass to firefox
when starting it from the command line in linux. You say you did that
and it didn't work? In what way exactly did it not work?

/path/to/firefox/firefox -safe-mode

typed in above command, got " no such file or directory ".

There is a a misunderstanding here. The intention is that you type the
full path to firefox, not the literal string "/path/to/firefox/firefox
-safe-mode".

It's also important to have a space between the firefox program and its
arguments

For instance, on my 9.10 box running firefox-3.5, that would be:

/usr/bin/firefox-3.5 -safe-mode

just

firefox -safe-mode

should work as it does here.

firefox --help

brings up all options

The part that says "/path/to/firefox/" needs to be changed to your
actual path to the firefox program. I forgot if you are using Windows
or Linux. On Linux, just open up a command line or terminal and type in:

firefox -safe-mode

Since firefox is usually stored in something like /usr/bin, or something
else in you PATH variable, you don't need the full path.

thanks all, i finally got it! if i had known about it last week, i might not
have had to re-install os after playing with a program that crashed.

Ok, the /path/to/firefox/firefox needs to be replaced with
the actual path to where firefox resides. On linux that is usually
in /usr/bin.