SuperCollider 3.4.2, released March 2011, is a bugfix release to make SC even more reliable.

Mac OSX downloads:

• http://sourceforge.net/projects/supercollider/files/Mac%20OS%20X/3.4.2/

Source code downloads:

• http://sourceforge.net/projects/supercollider/files/Source/3.4.2/

Since SuperCollider 3.4, we’ve found and fixed quite a few bugs - including an important “garbage collection” problem which could cause the language to crash in some rare instances, and a cleanup of the regular-expression methods. We recommend users of 3.4 to upgrade to 3.4.2.

More details on the wiki