how to install old version xcode

Old version xcode may cause installation failure on a relatively new version mac. To install xcode4.1 on lion 10.7.3, the solution can be:

 

1. Set the machine's date back to March 1, 2012. This works around the CSSMERR_TP_CERT_EXPIRED problem.
   
   
2. Then to skip the OS version problem, open a Terminal window and type:
   
   export COMMAND_LINE_INSTALL=1
   open /Volumes/Xcode/Xcode.mpkg/

However, during the installation process, you may encounter an alert dialog "in order to continue installation, please close the following application: iTunes". No matter how many times you open/quit itunes, the dialog refuses to disappear and the installation is stuck.It turns out that the background process “iTunesHelper” is still running, and also needs to be quit. To do this:

1. Open Activity Monitor (located in Applications/Utilities)
2. Start typing “iTunes” into the filter box in the top right
3. Select iTunesHelper from the list and click the Quit Process button.