When a program is hard blocked, the PCA will display a dialog box indicating that the program is blocked due to compatibility issues, and the program will not run. A Hard Block means that the program is known to be incompatible and running the program could result in severe system errors - such as causing a system crash or a no-boot scenario. So, what's the difference between the two?Ī Hard Block, as the name implies, means that this application either will not run or will not install on Windows Vista / Windows Server 2008. Depending on the nature of the issue, the application may be Hard Blocked or Soft Blocked. This list is maintained in the System Application Compatibility Database. When a user launches a program, if that program is on a list of programs that are known to have compatibility issues, then PCA informs the user of this. Let's get started with looking at Application blocking. Today, we are going to examine some program startup scenarios (specifically application blocking) and discuss the management of the Program Compatibility Assistant. In our previous post on PCA, we discussed several runtime issue detection scenarios. First published on TECHNET on Oct 05, 2007