Will updating to Mac Osx 10.6.8 Erase Data?

My iphone's running ios 6 and it got messed up so i wanted to restore it, itunes says it needs to be updated so when i downloaded itunes 7.1 it said mac needs to be updated. Do i have to install the mac osx update? Will it erase my data? ( i don't have a time machine or a back up)

Wow as mush as i hate to say it yes all will be gone because you will be replacing your partition when you install i do declare. But what happens if you want to keep that old data i recommend that you take your old hard drive out and take it to a copy company and ask them to take everything to disk then when you are installed and everything is ready to go just copy on your knew install and still have the copied information that you got from that company. But did you know that mac computers has a weak partition to begin with so if you notice that a lot of the data is missing go to clock and date and if they are wron than you need to use the tuneup diskett to reinstall all of your drivers then readjust the time and date then redownload what you had before the error this is the way to fix this problem.

The OS X update should not erase any data. However, there's always a slight chance that there will be a problem with the upgrade and that may result in data loss. There's a 95% chance everything will be okay, but it's always best to be paranoid and back up anything that's critical, just in case.