Signals the start of the processing proper, i.e., after the user pressed "Install", "Uninstall", etc. in the InstallMate user interface. Exactly which type of processing is performed, depends on pMessage->dwSessionType. At this point, all installation parameters are known (including the installation folder), but the target system has not been modified yet.

From this moment on, the extension DLL may perform its installation or uninstallation actions or make system modifications. The end of the processing is signaled by either a TIXMSG_END_PROCESSING or a TIXMSG_ABORT_PROCESSING message.

Action scheduling

This message is sent by the StartProcessing standard action; its scheduling depends on the action sequences used by the installer.


Not used

Result code

If this message is handled, pMessage->lResult must be set to one of the following result codes: