When an application is not Terminal Server aware (also known as a legacy application), Terminal Server makes certain modifications to the legacy application to make it work properly in a multiuser environment. For example, Terminal Server will create a virtual Windows folder, such that each user gets a Windows folder instead of getting the system’s Windows directory. This gives users access to their own INI files. In addition, Terminal Server makes some adjustments to the registry for a legacy application. These modifications slow the loading of the legacy application on Terminal Server and require up to 8 MegaBytes extra memory. This behaviour can be avoided if the TSAware flag is present in the PE header of an executable as can be read here at MSDN.

But how do we set this property in Delphi?

In Windows.pas we can see that the constant is defined:

But how to use this in your application?
Add the line

somewhere below the uses clause and we’re done!

Offcourse you are now responsible for making your application Terminal Server compliant which according to Microsoft means: If an application is Terminal Server aware, it must neither rely on INI files nor write to the HKEY_CURRENT_USER registry during setup.