Help! New Avast update killed my Mac

[Cynellezz]

Yesterday Avast showed that an update was available. I updated it. Then it wanted to reboot but now it will not restart. It gets stuck at the grey loading apple screen with the spinning circle thing. It's a Macbook running on Leopard.
It will not load in safe mode. Running verbose it shows that it gets hung up on AvastFileShield. I tried resetting the standard things but the only thing I can get into is single user mode. The problem is that I don't know the commands required to find and disable or delete Avast so that I can get my computer to load. Can anyone help?

[Cynellezz]

I should add that my optical drive isn't an option either because it's pretty much been defective since I bought the computer. I'm used to command line interface with Dos but not with Unix which is why I need the help.

[.: Mac :.]

Reboot your in safe boot mode:

1-Shut down your Mac and wait 10 seconds.
2-Press the power button.
3-Immediately after you hear the startup tone, hold down the Shift key.
4-You should press the Shift key as soon as possible after you hear the startup tone, but not before.
5-Release the Shift key when you see the gray Apple logo and progress indicator (spinning gear).

This method disables loading most startup items and should allow your computer to boot. Then uninstall avast and reinstall with the current version from the website

[specimen9999]

Reboot your in safe boot mode:

1-Shut down your Mac and wait 10 seconds.
2-Press the power button.
3-Immediately after you hear the startup tone, hold down the Shift key.
4-You should press the Shift key as soon as possible after you hear the startup tone, but not before.
5-Release the Shift key when you see the gray Apple logo and progress indicator (spinning gear).

This method disables loading most startup items and should allow your computer to boot. Then uninstall avast and reinstall with the current version from the website

To uninstall avast completely, the only "easy" way is via the uninstall menu entry in avast. which requires avast to be running, in safe mode avast isn't loaded, so you don't have the uninstall option.

Now, I'm sure there's a command line way to run this uninstallation and remove avast completely (not just the app), or at least a description of what should be deleted by hand, I just can't find any up to date reference on that.

[mity]

Sad to hear it. We got messages about this happening to few users yesterday and I provided experimental fix in this thread:
http://forum.avast.com/index.php?topic=116250.0

If you have problem to boot at all, you can uninstall from the single-user mode. To do so, press <APPLE>+<S> during boot, more info is here:
http://support.apple.com/kb/ht1492

After you boot there, you should be on a prompt beginning with '#' character. Type one after one the following commands carefully and commit each one with <ENTER>:


/sbin/mount -uw /
"/Library/Application Support/Avast/install.sh" uninstall
reboot


Regards,
Mity

[Cynellezz]

Thanks for the help - trying the suggestion by Mity now. My computer won't start in safe mode with the shift key (the loading bar only goes part way and then disappears with the endless apple loading screen) so single user mode is the only option I have.
So far after running the "/Library... command it showed a Kext error not able to find com.avastshield
I'm going to try again as the computer is still trying to reboot and stuck on the grey apple loading screen again. If the message pops up again I'll type it here exactly.

[Cynellezz]

Well had the 2 errors with not being able to find the 2 Avast files to uninstall. My computer is still not loading and it is having trouble trying to find certain files in the Library for other diagnostic commands. It's not showing that it's getting hung up on the missing file now but it's still freezing. Any other ideas?

[mity]

Safe mode and single-user mode are different things. I suggested to boot in single-user mode. Hold <APPLE>+<S> during boot, not <SHIFT>.

[Cynellezz]

Correct. Like I said above, I can't boot into safe mode - I get the progress bar and then nothing. I have only been able to boot into single user mode (command + S) since this whole debacle began. When I performed the actions you reccommended I got 2 Kext errors with the system not able to find 2 of the Avast files to uninstall.

Safe mode and single-user mode are different things. I suggested to boot in single-user mode. Hold <APPLE>+<S> during boot, not <SHIFT>.

[mity]

Can you be more specific? What errors you get?

Mity

[REDACTED]

I have a same problem.safe mode does not start avast was instaled yeastrday now nothing helps to run my mac.please assist with options