how can i go back to safari 5.1.7

Try this...

http://mac.softpedia.com/progDownload/Safari-Download-25616.html

You might need this first...

http://adcdownload.apple.com/Safari/safari_6_developer_preview_2_for_lion/safari _6_developer_preview_2_for_lion_uninstaller.dmg

http://apple.stackexchange.com/questions/57916/how-do-you-remove-safari-6-on-mac -osx-10-7-4

This is the solution - luckily 6 keeps a backup of 5.

There are two posted up there - either follow the instructions for unpacking the backup version, or download 5.1.7, delete 6 and reinstall 5. Which bit don't you understand?

If you have Lion the following method is relatively painless (Mountain Lion removed the OS X RSS supporting code so Safari v5.1.7 won't run on Mountain Lion) - assuming you have access to an installed package of Safari v5.1.7.

Leave v6.0 where it is.

Find another installed Safari v5.1.7 source (time machine, or a Mac that wasn't updated - Snow Leopard Macs did not get the v6 update). For a Mac that wasn't updated go into the Applications folder copy the Safari package (its the Safari Application with the Safari icon in Applications directory) - it should be about 40MB in size if memory serves.

On your Safari v6.0 Mac, go into your Applications folder and create a new folder (I called mine Old Safari), then drop your Safari v5.1.7 copy into it. Copy the Safari v5.1.7 to the dock so you can launch v5.1.7 easily (I deleted my v6 Safari icon for clarity Dock but its not required).

Run v5.1.7 and enjoy its functionality again (its what I'm typing this in and others have used this method) and any updates that come for v6 should find the installed v6 and update it.

Important, do not run both versions at the same time (they use the same supporting files and corruption is likely) and just to avoid issues if you are running v5.1.7 I'd avoid using v6 till your ready to give up the ghost on v5.1.7 (who knows what kind of issues could raise their heads with them both using the same supporting files).

At some point, with this method, you could do an update from Apple that updates the underlying supporting code Safari uses and breaks Safari v5.1.7 (like disable the Lion OS X RSS functionality) so that's an ongoing danger, but this is an option for folks that want to use v5.1.7 again and can't roll back their machines.

Of course v6 had a bunch of security issues fixed so using v5.1.7 presumably leaves those and future updates behind - so this isn't a great long term solution, but for now it works.

Clear instructions here:

http://coderwall.com/p/ndm-iw

I've had nothing but problems with Safari 6 on the last vers of Lion... constant crashing and general instability...

I've tried all possible methods to try and revert to 5.x... nothing works... if i reinstall 5.x in any way it will just crash... as far as i can see it's not possible to downgrade from safari 6 - it is too heaviily embeded in the OS and its current version... so ultimately the options seem to be: revert to a previous vers. of the OS before Safari 6, live with vers 6 or just switch to firefox or chrome...

Safari 6 is preventing me from upgrading to Mountain Lion. It's so bad.

There's an uninstaller for 6 here (note this was used for the beta versions of 6, not sure how it'll work with 6.02 test at your own risk):

http://steevepatrick.com/#how_to_uninstall_safari_6_lion

This will only work on people using OS X Lion (10.7.x) and will not work on Mountain Lion (where 5.1.7 will not work).