after we converted ISL to ISM(2018), when we try to open the same in Visual Studio 2012, it is not getting loaded.
show as unloaded project, is there anything we can do about this.?
You need to have either InstallShield 2018 Professional or Premier edition installed to work with .ism files. InstallShield limited edition cannot open or build projects if it has anything above the capability set of the Limited Edition.