Q: Safari crashes upon launching. Immediately.

Safari crashing may be due to extensions or third party plug-ins.

Troubleshooting help here > If Safari is slow, stops responding, quits unexpectedly, or has other issues - Apple Support

Adware may be installed on your Mac without your knowledge.

How to remove adware?

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.

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.

Hi Derek.

Most of the times the issue could be due to Safari Extension, Internet plug-in, or other add-on. To troubleshoot this issue, turn off Safari Extensions. To do so, open Preferences from Safari Menu. Then click Extension icon, and deselect Enable checkbox to turn off that extension. If doing this doesn't work, then try removing Internet plug-ins and other add-ons. To know more about it, please see the article below. It is from Apple website.

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

If you still face the same issue, please let us know.

Thank you.

If the problem comes back,

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

Dominic —

I think this may have worked. Tried all instructions this morning, and Safari has been on without a crash/quit since. MalwareBytes detected several issues. I didn't note them, unfortunately, but the app says it cleared them.

Thank you, ever so much.

Derek, try deleting Safari folder from Finder. To do this Go To Finder> Press ALT then go to Library and locate the Safari folder. Delete the folder and try launching.

If it works let us know.

Thanks for the response.
I tried Dominic's instructions (above), and everything seems to be back to normal. I'll refer to your advice if something goes wrong down the line.

Cheers.