Q: New Safari 6 installed on 9/24/2014 will not quit.

Safari 6 doesn't run on Mavericks. Please check the version number.

So the instructions linked below don't work?

OS X: How to quit an unresponsive application using Force Quit

If that's so, you'll have to force a restart. Press and hold the power button for a few seconds until the power shuts off, then release, wait a few more seconds, and press it again briefly to restart.

If the same thing happens again, see below.

Please read this whole message before doing anything.

This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.

The purpose of the test is to determine whether the problem is caused by third-party software that loads automatically at startup or login, by a peripheral device, by a font conflict, or by corruption of the file system or of certain system caches.

Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards, if applicable. Start up in safe mode and log in to the account with the problem. You must hold down the shift key twice: once when you turn on the computer, and again when you log in.

Note: If FileVault is enabled, or if a firmware password is set, or if the startup volume is a software RAID, you can’t do this. Ask for further instructions.

Safe mode is much slower to start up and run than normal, with limited graphics performance, and some things won’t work at all, including sound output and Wi-Fi on certain models. The next normal startup may also be somewhat slow.

The login screen appears even if you usually login automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.

Test while in safe mode. Same problem?

After testing, restart as usual (not in safe mode) and verify that you still have the problem. Post the results of the test.

I had the same problem.  Cannot quit.  Quit in the menu bar greyed out.  x's to close tabs gone missing.  Had to kill the process in the activity monitor.  This is an obvious bug, that we will just have to wait for Apple to fix.

I have reported a similar problem - recent - with Safari in Snow Leopard -- I use separate windows rather than tabs - Safari was not quitting.

Force quit showed 2 Safari's -- apparently, when I closed the initial search window after 2nd window opened - it kept running as separate safari job -

Have noticed for a while some websites with too many icons, rolling banners etc - don't like have load stopped or don't recognize stop request so seem to continue on loading.   - Shutdown  was the only way to clear.

So use the Safari option to report bugs to Apple -- or call apple support.     Be clear on what  you were running at the time.