I had problems trying to convert and build InstallShield 2013-projects into InstallShield 2018-projects into Visual Studio 2017.


-1- When you open the solution containing your C#-project and your InstallShield-2013-project in Visual Studio 2017, the InstallShield-2013-project is labelled "(incompatible)".
When you leave the mouse on the InstallShield-Project, it appears a Tooltip showing "the application is not installed". A "Repair" with the "InstallShield 2018 - InstallShield Wizard" doesn't solve the problem.
Previous Version of InstallShield (for instance 2016 as far as I could test) could automatically convert InstallShield-2013-project within VS2017. It seems, it doesn't work any more. Just remove the InstallShield-2013-project from your solution.

-2- Open the "InstallShield 2018"-program and open the InstallShield-2013-project (file .isl). A dialog appears. Accept to convert the project.

-3- Back to Visual Studio 2017. Add the InstallShield 2018-project (file .ise) to your VS2017-solution again.

-4- When you open "Project assistant/General Information" you don't see the point "Setup Language" anymore (I use normally "German")

-5- When you build the InstallShield 2018-project, you might get "some" warnings like (see output-window or log file):
....
ISEXP : warning -3028: The string ID "DN_AlwaysInstall" was not found in the string table. It is referenced in the table:"Feature" in column:"Title".
ISEXP : warning -3028: The string ID "DN_AlwaysInstall" was not found in the string table. It is referenced in the table:"Feature" in column:"Title".
ISEXP : warning -3028: The string ID "DN_AlwaysInstall" was not found in the string table. It is referenced in the table:"Feature" in column:"Title".
Setup.exe created
Automatic update notification disabled
Express\DVD-9 - 0 error(s), 1149 warning(s)

-6- It seems that InstallShield 2018 doesn't recognise the "Setup Language" and uses "English (United States)" per default
...
Language English (United States) built
Files built
Media table successfully built
ISEXP : warning -3028: The string ID "DN_AlwaysInstall" was not found in the string table. It is referenced in the table:"Feature" in column:"Title".
ISEXP : warning -3028: The string ID "DN_AlwaysInstall" was not found in the string table. It is referenced in the table:"Feature" in column:"Title".
...

-7- As you notice (see above) the Setup was created in the directory "...\Express\DVD-9".
For my InstallShield-2013-projects I always choosed "DVD-5" as Media Type. In this case the directory was "...\Express\DVD-5" (and still exists on my harddisk)

-8- In order to change the Media Type you can open the Configuration Manager (menu "Build") and put "Configuration" to what you had previously (in my case I put "DVD-5")

-9- You should be able to build your new InstallShield 2018-project without errors or warnings