>How does one detect whether the app was previously installed and offer to
>uninstall first prior to new install?

Sim,

What Geoff said. SB's Run Program does have a Wait for Program option. Here's
some other things that come to mind.

Developer Edition has a Detect Previous Version script item that sets a
variable to the path to the previous version, if detected. With that you can
execute your uninstall like so: PathToYourUninstall.exe /U
"PathToYourUninstall.log". Be sure to quote the install log path if it
contains spaces.

Search for File in the Developer Edition is an alternative to Detect Previous
Version. You could use it to search for your exe and/or your uninstall
program, executing the uninstall after verifying the log file exists.

If you have to be sure the uninstall completed successfully, SB's Run Program
sets % SB ERRORCODE% to zero on success. I don't know if that's an indication
of successful execution by the OS, or an exit value from the run process. It
would be easy enough to verify the program no longer exists, if needed.

Using either of those methods to detect the program's existence, you could
simply display a message asking the user to uninstall the previous release,
and then exit the script.

--
Best regards,

Mark

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