Will I lose my data if I restore OS X mountain lion?

In theory nothing, but oops do happen, so make at least one backup before re-installing.

Do a backup. Boot to the Recovery Volume (command - R on a restart or hold down the option key during a restart and select Recovery Volume). Run Disk Utility Verify/Repair and Repair Permissions until you get no errors. Then re-install the OS.

OS X Recovery

OS X Recovery (2)

It depends on how your "restore" Mountain Lion. If you wipe your disk clean and reinstall the OS, you will lose all your data. If you just reinstall the OS, the data on your disk should remain. However, before doing either, have you tried booting with the Shift key down? You will then be trying to boot into Safe Mode, which does some maintenance and disables third party software which may be causing the problem. See if that allows you to start up. If so, you may not need to reinstall the OS.

Frome Cottage wrote:

HHi Eric,

THanks for responding. My disc titled Macintosh HD cannot br repaired via disc utility but a second disc titled Mac OS X base system is working ok. when looking in the info tab, the libraries come up for photos, music etc but cannot be opened on either disc. How can I back up from this position?

You need to run Verify and Repair Disk from your Recovery HD, not inside Mountain Lion. So, do what Eric suggested by restarting into the Recovery HD by pressing/holding the Command+R keys when you restart. Launch Disk Utility from the OS X Utilities Menu and Verify Disk on the Macintosh HD. If errors are found, then do Repair Disk. Try this before you decide you have to reinstall OS X Mountain Lion.

There is a way to back up your system via the OS X Utilities from the Recovery HD.

Boot into the Recovery HD using either Recovery Mode or Internet Recovery.

At the OS X Utilities Menu, select Disk Utility.

Plug in a USB external drive. Make sure you have a partition larger than your Macintosh HD and the drive is formatted as Mac OS Extended (Journaled) with the GUID partition table.

Select your Macintosh HD then click the Restore tab.

Select your Macintosh HD as the Source and the USB external drive as the Destination. Click the Restore button. This will block copy your Macintosh HD over to the USB drive. It's basically a clone.

Once the above steps are done you can format your Macintosh HD and Reinstall OS X.

This post just saved me 300 bucks I was really hoping to NOT pay hard drive recovery guys. Thanks!

I wish had read this before starting a reinstall. T__T My laptop would only boot to recovery mode and AppleCare told me that reinstalling OS wouldn't damage my data and that there was no way to get a back-up, unless I reinstalled the OS.. I stupidly listened to them and now am waiting for the installation to finish terrified that I'll lose 1TB of data... I wanted to make a back-up, but apple told me it wasn't possible. ://

Am having the same problem. OS X 10.10.

System does not boot up. I tried in safe mode too, but it doesnt even let me start in safe mode. When I press the shift key after the bootup sound,, nothing happens but the password screen comes. I type the password, booting bar comes in & hangs at half way.

Tried verify & repair with recovery options, no error found. Anything else to try?

Also,, wen i tried to backup the data with ur instructions, am unable to drag drop or select my Macintosh HD disk, its disabled. am unable to select in the source box. Wat do I do?

Startup Issues - Resolve

Startup Issues - Resolve (2)

Startup Issues - Resolve (3)

Boot to the Recovery Volume (command - R on a restart or hold down the option/alt key during a restart and select Recovery Volume). Try using Disk Utility/Restore to copy the backup to a new location. Please note that this will reformat the destination partition.

Data recovery is not difficult for normal data loss problem, but if the hard drive is damaged, then the first thing you need to pay attention to is fixing the hard drive.

But you need to notice that after fixing the hard drive, all the files are gone and it seems like it is a new hard drive. At this moment, don't put any new files into the drive 'cause if this happens, you will meet data overwritten situation and if this happens, the chance of data recovery will be reduced.

Maybe you can try uFlysoft Data Recovery for Mac, it can recover DATA on Mac only in three steps:

Step 1. Launch the software to scan the device where your files deleted

Step 2: Preview the scan result files and make mark if it is the one you find

Step 3: Recover files