There are a few common reasons for Safari to constanly crash.
1) Corrupted user preference file.
Look in your user preferences folder
(~/Library/Preferences/), located at:
[hard drive]/Users/[your user name]/Library/Preferences
for:
com.apple.Safari.plist
Drag that file to the desktop and restart. A new preferences file
will be created in your user preferences folder when you launch
Safari the next time. See if things are better. If they are, you
can trash the Safari preferences file that you now have on your
desktop.
There is another preferences file that is often implicated with Safari crashing:
com.apple.quicktime.plugin.preferences.plist
Try uninstalling it too.
2) Repair permissions on your hard drive.
See:
OS X Maintenance And Troubleshooting
Item #1
3) Corruped cache.
Download and run:
CacheOutX (free)
TriLateral Systems - Welcome
to clear out your caches. (Choosing Reset Safari will also clear some caches, as will performing a Safe Boot. CacheOutX will do a more thorough job.)
If none of the above help, a comprehensive list of further suggestions
can be found at:
Tutorial: What to do when a Mac OS X application will not launch | MacFixIt - CNET Reviews
___________________________________________
Randy B. Singer
Co-author of The Macintosh Bible (4th, 5th, and 6th editions)
Macintosh OS X Routine Maintenance
OS X Maintenance And Troubleshooting
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