Q:

Restore MacBook after Avast! install (stuck at apple logo)

Somebody installed Avast! on this MacBook running OSX 10.8 (that's what uname said) and now it won't boot, it gets stuck at the apple logo and nothing more, I was able to boot into single-user mode and made a backup. I have already run Avast!'s uninstall script at:
/Library/Application Support/Avast/components/uninstall/com.avast.uninstall.app/Contents/MacOS/uninstall.sh

But it didn't solve anything.
How can I restore my MacBook? How can I make it boot normally? I am a complete noob using Apple products.

A:

Try this link:  https://forum.avast.com/index.php?topic=151393.15
part way down the first page of the thread, the poster Francisco Velasco had a solution that worked for me (his is reply #9 August 17, 2014). Good luck, and steer clear of Avast Antivirus - I'm going back to ClamX AV!!

Turn off your Mac, press Command + S, turn on, and don´t release Command + S until you see the Apple logo  
When you are in the prompt (a black screen with white letters), type
/sbin/mount -uw / < ENTER >
Work through these commands, in sequence:
cd Library < ENTER >
cd Application\ Support < ENTER >
(as there is a space between "Application" & "Support", we use \ after Application then a space)
cd Avast < ENTER >
cd components < ENTER >
cd uninstall < ENTER >
cd com.avast.uninstall.app < ENTER >
cd Contents < ENTER >
cd MacOS < ENTER > 
Now, in this last folder if you type
ls < ENTER >
You will see a file called uninstall.sh, and this is the one to run to remove
Avast, now to use it you must use the following instruction
sudo sh uninstall.sh < ENTER >
After this now you can reboot your Mac
reboot < ENTER >
If after this reboot you can´t login your Mac, turn off your mac, repeat step 1 and 2 and now go to the folder
cd private < ENTER >
cd etc < ENTER >
ls < ENTER >
and you see a file with the name launchd.conf, you need to delete this file, type the following
rm launchd.conf < ENTER >
Reboot your Mac with
reboot < ENTER >

