Yosemite crash

Hi, my MAC after turn ON, half way loading then it shut down, try reset everything include PRAM still same problem.

Start by trying to boot into Safe Mode

<http://support.apple.com/kb/ht1564>

If you can get booted in Safe mode, see if you have kernel panic reports

Kernel Panic reports: "/Library/Logs/DiagnosticReports"

<http://support.apple.com/kb/ht2546>

<http://support.apple.com/en-us/HT200553>

The panic report should have "panic" in the file name.

If you do have kernel Panic reports, please post 2 or 3 as replies to this thread.

If you cannot boot into Safe mode, try recovery mode, and run disk utility to check your boot disk

<OS X: About OS X Recovery - Apple Support>

Now I want to try reinstall the OS, will it wipe the drive? I don't have backup so it's very important not to remove the file.

Generally, installing the OS over top of an existing install will not erase things, HOWEVER, unless you are re-installing the same version or a newer version, often times the installer will not install an older version on top of a newer version.

NOTE: I would try to get the current system booted if possible, before going down the re-install path.

In theory you could use Recovery mode and Disk Utility to make a backup

You could also use Recover mode to make a clean OS X install on an external disk, and then use that external disk to salvage data from your boot disk.

If there is an Apple Store near by, make a Genius Bar appointment, but MAKE SURE they do not do anything that will erase your disk. You can always say "Thank You", and go home to consider other options if it comes down to a reformat.

I would try the Recovery Mode -> Disk Utility -> Select an external disk, then Disk Utiliyt -> Edit -> Restore where you specify the internal disk as the "Restore From" device, and an external disk as the destination, and see if you can get a backup.

If that doesn't work, I would see about installing a new OS X on an external disk from Recovery Mode (or another Mac), then boot from the external disk and see what you can do to backup your internal disk.

Once you have a backup (2 would be better), you can reformat the internal disk, install a clean OS X, then restore your data from your backup(s).

Feel free to get a 2nd opinion 🙂

Startup Issues - Resolve

Startup Issues - Resolve (2)

Startup Issues - Resolve (3)

Google found this post, but I'm not sure they actually really resolved the issue.

<https://apple.stackexchange.com/questions/155209/macbook-pro-2011-rebooting-on-s tartup>