Q: Hi, My Mac stucks at prohibitory symbol... So, if i'm going to use reinstall OSX options, my data on MacintoshHD will be wiped out from it or not? Pls help me...

Don't tell us you didn't back up your data! Hopefully it will not get lost while reinstalling the OSX.

Pete

You should always have data backed up. All the time. These are the exact situations where you now may be caught out and lose all your data due to not having a backup strategy in the past. Basically now it may be too late. But you  have no option now than to reinstall, so good luck and I hope it all goes well.

Cheers

Pete

If you boot to Recovery

OS X: About OS X Recovery - Apple Support

does disk utility see and mount the drive?

If so then you can either:

- Via Recovery install OSX on an external drive and then try to recovery data from the internal drive.

- Via Recovery clone the disk to an external disk

http://www.newertech.com/tech_support/manuals/mac/clon_data.php

and then repair/format the internal drive and try to install OSX. Then try to recovery data from the clone.

The problem may be due to a bad cable connecting the disk to the logic board or a poor connection. Or the drive could have failed.

A data Recovery company might help in that case