In my projects installscript I uninstall previous versions before installing the current version of the software. But when I run the setup file created by installshield, I always get the error 1618: “Another installation is already in progress. Complete that installation before proceeding with install.” Scenario is like this: If I have two previous versions, I expect two uninstaller process run completely before one installer process run. Looking at the error above, it feels that these processes are running concurrently or in a random order: From the system restore, this following is the timing of process initiation. Uninstall - 13.33.11 Install - 13.33.11 Uninstall - 13.33.11 Sometimes the installer is started first, while I expected the uninstallers to finish the job first: Install - 16.17.14 Uninstall - 16.17.21 Uninstall - 16.17.27 To launch these uninstallers/installers, I use APIs such as “LaunchAppandWait” with LAAW_OPTION_WAIT and/or “LaunchApplication” with INFINITE timeout. So I expect these processes to wait until it terminates before moving on to the next. But apparently it is not like it and the problem still persist. Could you please let me know if this is a known issue? Any solutions would be appreciated? ... View more