Unload application disabled /greyed out in IIS

In IIS6 application unloading / recycling is handled differently. You may notice that the "Unload" button is greyed out or disabled in the Application Settings area. This is because the application is in native IIS 6 mode using application pools. Synonymous to unloading the application in IIS 5 is the concept of recycling the application pool in IIS6, see the Application Pools folder in IIS manager (inetmgr). The only time the Unload button will work is if the IIS web service is running in IIS 5.0 isolation mode and the Application Protection is set to either Medium or High.