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I started playing with a Mac just a couple of days ago, and it seems, without warning I've caused some major damage.

The system is running OS X version 10.5.8, and without paying much attention, I replaced the system supplied libxml2 (/usr/lib/libxml2.2.* ) with a new version that I compiled --- I should have paid more attention to just creating a local copy of everything, and not touching the system directories, but tooo late for that now!)

What I did not reckon with was that doing so breaks the entire system, because I didn't know how fundamental libxml2 is to everything on a mac.

Before clobbering the system libxml2 with my own, I made backup copies --- but those copies are useless because with the new libxml2 that I put in there, no important command like "sudo" etc. works anymore --- (Finder, System Prefs, etc., everything has stopped working).

How can I repair the system to restore to it the clobbered files?

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up vote 1 down vote accepted

Here's the first thing to try, depending on how damaged your system is.

Try booting into Single User Mode. That will give you a very simple root shell which will bypass nearly everything else. I can't guarantee that the stuff you'll need will work without libxml, but it's likely.

To do this, boot while holding down the Command and S key. It should boot into a shell. Follow the onscreen directions to fsck and remount the filesystem as writeable, and restore your backup copies.

Apple Examiner has an article with more details on the process.

If this doesn't work, you may need to find your install discs and see if you can get to a terminal from there.

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Thanks a ton!...fortunately, since i had made backup copies, single user mode bootup was sufficient for me to restore the clobbered files! Awesome! Once I've some more rep on this site, i'll be able to do a +1 too! – suvrit Oct 15 '12 at 20:51

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