How to install the new OS X

Unless you instruct the installer otherwise, it will overwrite the existing OS but not your documents and other files, which are part of the Time Machine backup.

(73737)

The to be on the safe side before you start the download of the new OS do a complete system backup using Time Machine.

Once you download the new OS and start the install it will just overwrite the OS files already on your system and Should preserve, That is SHOULD, all your programs and personal files. But like anything dealing with computers anything can happen. That is the reason for doing a complete backup before you start.

Unless you have a reason to do it differently, perform a default installation and don't add additional steps or complexity to the process.

(73738)

I personally don't do that, even with Mac OS X, but other seem to find it works OK.

If you chose to first erase the drive during the first part of the new OS install then instal the new OS to a Clean drive if you have made the compplete system backup as I suggested you can use the Setup assistant system to copy over Programs, Settings and Personal files from that backup you made just before you started the process.

Biochemist69 wrote:

is it good to over write the existing OS ? i think its better if i delete everything and then install the new OS. I might be wrong .. what you think ?

Sure that is what Time Machine is for. Restoring the complete system or parts of it.

I take it you have never used Time Machine or any type of backup system.

A word of caution. If you never have backups of your data "You Will Lose All Of It at Some Point. That is a fact of computers as they all fail.

Biochemist69 wrote:

so i can restore my photos music and documents from time maschine ?

Yes. Note that the default installation won't erase your files or make restoration necessary.

(73741)

Well you can manually save then before you start then copy them back if something goes wrong. But YES TM SAVES all that already and can restore just that and a lot more.

Look at it this way. If you do a TM backup NOW and then when that is done you download and install Mt Lion. If something goes wrong you can use that TM backup to put your system back to Exactly the way it was Before you did the download and install of Mt Lion.

No real option. The Default is to install over the top of the current OS. You have to Manually Erase the Macintosh HD partition using Disk Utility included in the new OS setup system then continue with the install.

Biochemist69 wrote:

ok ... So there is an option to do default installation and clean install ?