Many thanks to you for your insights! This made it possible for me to follow your procedure and to make my own insights. In case anyone comes across this post, I add them here for completeness (for use on your own risk 😉). Switching to 64-bit signing is documented here (for InstallShield 2022): https://docs.revenera.com/installshield28helplib/helplibrary/ConfiguringPlatformArchitectureforDigitalSigning.htm I wrote a small tool called "ISSign64.exe" and copied it to folder "\system" of the InstallShield directory. The tool writes all parameters passed to it to a file (one line per parameter). I noticed that during every invocation of the tool a file with 10 lines was written to disk. I interpretate these lines/parameters as follows: Full pathname of the file to sign C:\Program Files (x86)\InstallShield\2022\System\SignTool.exe This was always the same. This file obviously does not exist in the latest versions of IS (as stated in the initial post here). But one could take it from the Windows SDK (https://developer.microsoft.com/en-us/windows/downloads/windows-sdk/) or make use of another tool. Full path to certificate as specified in the IS GUI, but with added "?auto" at the end Filename (not full path) of the file to sign, but without file ending For example no ".msi" at the end Certificate URL as specified in the IS GUI http://timestamp.digicert.com Most probably as specified in "Settings.xml" (DigitalSignature Timestamp) http://timestamp.digicert.com Most probably as specified in "Settings.xml" (DigitalSignature TimestampRFC3161) Password of certificate as specified in IS GUI Empty Empty As of now, I don't know why the last two items are empty. Maybe the result from input I did not give in the IS GUI. So, I hope this may be helpful to someone. And thanks again to jchittock for raising this topic! ... View more

Thank you for sharing this! Now I'm curious about this "ISSign64.exe" and would like to know more about it and how it can be used. Unfortunately calling this tool with options like "-h", "--help" or "/h" does not show any help text. And I could not find anything about it within the InstallShield Help Library either (F1 help). If you are aware of any publicly available information, please feel free to let me know. ... View more

Maybe "iSign.exe" within the folder "\system" of InstallShield is the tool you are looking for. Calling it with no arguments shows this help text: ... View more