Blackra1n is so far the easiest way to Jailbreak your device, but still users have got several issues while using it. Technically, it’s not the fault of developers, but its blame to be put on users who might be doing something wrong during the whole process. The following guide will highlight few cautionary steps you need to take care of before starting:

• Make sure you’ve upgraded to 3.1.2. Blackra1n
  jailbreak does not work for 3.0 or 3.1.
• Download the Blackra1n tool to your desktop. Some users have reported
  issues of the application crashing or having
  issues with rights on Vista or Windows 7. This should fix those
  issues. You can also try running it as Administrator
• Close all other applications when you
  jailbreak to avoid interference. Also its better if you terminate “mdnsresponder” process in your Task Manager
• You won’t lose any of your apps or data. You can always sync your iPhone to iTunes to restore everything as it was before.
• If you have a
  white screen turn off the device by holding the power and home buttons for 10 seconds and boot it again.
• If iTunes keeps popping up, go to the task manager and kill all iTunes processes which includes iTunesHelper.exe. This can cause interference with the process too.
• Reboot your device and Enable the “Airplane” mode. It has also helped out few people.
• There have been some compatibility issues with Vista and Windows 7. You need to set it right by going to its properties, and enabling “Windows XP Compatibility Mode”
• If your device doesn’t boot for a long time, hold down the power and home buttons and restart it. If it tells you to connect to iTunes, something must have gone wrong and you might have to restart the process. I know this is annoying, but it has worked for some people after some tries. It does work.
• Strangely, doing the process on different computers has also worked for some people.

In the end, the process DOES WORK. Though there are some bugs, but they can be overcome with a little effort. This procedure has been tried several times and it has been successfully completed by most of the users.

Even if you fail during the process, try it again or try it on a different PC. Just keep in mind that thing crack works, now you have to make it work for your device.

Have got questions or queries in mind? Feel free to comment below.