Q: Safari quits all of a sudden?

Update Safari.

Get the latest version of Safari for your Mac

If Safari is slow, stops responding, quits unexpectedly, or has other issues

https://support.apple.com/en-us/HT203353

Sometimes installed adware can cause this problem.

You will have t do this after starting up in Safe Mode to prevent adware

from interfering with the removal of adware .

1. Shut down the computer.

    Press the power button. Immediately after you hear the startup sound,

    press and hold the Shift key.

    The Shift key should be pressed as soon as possible after startup,

    but not before the startup sound.

    Release the Shift key when you see the Apple logo on the screen.

    Startup will take longer than usual.

    Screen flickering is normal in Safe Mode.

    Login to your account. Launch Safari.

    Enter this address       https://www.malwarebytes.org/antimalware/mac/

    in the Safari address bar.

    Download,   Install , open,  and run it by clicking “Scan”  button   to remove adware, if present.

    Once done, quit MalwareBytes.

2. Safari > Preferences > Extensions

    Turn all extensions off

     or  uninstall all extensions you haven’t installed knowingly.

3. Safari > Preferences >  Search > Search Engine :

    Select your preferred   search engine.

4. Safari > Preferences > General > Homepage:

     Set your Homepage.

5. Restart normally from  menu in the menu bar.

If this doesn’t help, please run EtreCheck and post the report here.

http://etresoft.com/etrecheck

Download it, open Downloads folder, click on it to open, select”Open”  in the dialog to run it.

Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste it when you reply.

Safari 9

Safari/Preferences/Advanced - enable the Develop menu, then go there and Empty Caches. Quit/reopen Safari and test. Then try Safari/History/Show History and delete all history items.  Quit/reopen Safari and test. You can also try try Safari/Clear History…. The down side is it clears all cookies. Doing this may cause some sites to no longer recognize your computer as one that has visited the web site. Go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J.  When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder.  Select Library./Caches/com.apple.Safari/Cache.db and move it to the trash.

Go to Safari Preferences/Extensions and turn all extensions off. Test. If okay, turn the extensions on one by one until you figure out what extension is causing the problem.

Safari Corruption       See post by Linc Davis

Safari 8

Safari/Preferences/Advanced - enable the Develop menu, then go there and Empty Caches. Quit/reopen Safari and test. Then try Safari/History/Show History and delete all history items.  Quit/reopen Safari and test. You can also try try Safari/Clear History and Web Site Data. The down side is it clears all cookies. Doing this may cause some sites to no longer recognize your computer as one that has visited the web site. Go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J.  When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder.  Select Library./Caches/com.apple.Safari/Cache.db and move it to the trash.

Go to Safari Preferences/Extensions and turn all extensions off. Test. If okay, turn the extensions on one by one until you figure out what extension is causing the problem.

Safari Corruption       See post by Linc Davis

10.9 and lower

Safari/Preferences/Advanced - enable the Develop menu, then go there and Empty Caches. Quit/reopen Safari and test. Then try Safari/History/Show History and delete all history items.  Quit/reopen Safari and test. You can also try try Safari/Reset Safari. The down side is it clears all cookies. Doing this may cause some sites to no longer recognize your computer as one that has visited the web site. In Finder hold down the option/alt key while selecting the Go menu item. Select Library. Then Library./Caches/com.apple.Safari/Cache.db and move it to the trash.

Go to Safari Preferences/Extensions and turn all extensions off. Test. If okay, turn the extensions on one by one until you figure out what extension is causing the problem.