Apple has published [in a support document a list of incompatible software](http://support.apple.com/kb/HT3258) for Mac OS X 10.6 Snow Leopard.
When you install Snow Leopard or upgrade to Snow Leopard, the operating system by default moves known-incompatible software to a folder named “Incompatible Software” on your hard drive. The list of incompatible software includes:
* Parallels Desktop, version 2.5 and earlier
* McAfee VirusScan, version 8.6
* Norton AntiVirus, version 11.0
* Internet Cleanup 5, version 5.0.4
* Application Enhancer, version 2.0.1 and earlier
* AT&T Laptop Connect Card, version 1.0.4, 1.0.5, 1.10.0
* launch2net, version 2.13.0
* iWOW plug-in for iTunes, version 2.0
* Missing Sync for Palm Sony CLIE Driver, version 6.0.4
* TonePort UX8 Driver, version 4.1.0
* ioHD Driver, version 6.0.3
* Silicon Image SiI3132 Drivers, version 220.127.116.11
Snow Leopard also prevents known-incompatible software from opening. The list of software that Snow Leopard will not open and run:
* Parallels Desktop, version 3.0
* VirusBarrier X4, version 10.4.4 and earlier
* SPSS 17, version 17.1
* Director MX 2004, version 10.2
* EyeTV, version 3.0.0 to 3.1.0
* Ratatouille, version 1.1
* AirPort Admin Utility for Graphite and Snow, version 4.2.5
Visit Apple’s [Snow Leopard Support Page](http://www.apple.com/support/snowleopard/) for more help on installation, manuals and tutorial.
For a more comprehensive list of what software runs with Snow Leopard, visit [Mac OS X 10.6 Snow Leopard Compatibility List at Wikidot.com](http://snowleopard.wikidot.com/).