Context: Glimpse at an internal thread where Technical Evangelists were asking about Affects of a Vista Upgrade on Existing Application Installs
Question 1: What will happen to the installed programs at the time of OS upgrade?Will the user be able to uninstall the program from vista if it is installed in XP? Answer 1: During upgrade, no programs are installed or uninstalled via MSI. They will be present after upgrade, and upgrade design is for them to be uninstallable.
Question 2: What will happen to the files cached in the Windows\installer folder at the time of OS upgrade?? Will they be carried forward AS IS in upgrade Vista OS? Answer 2: Yes.
Question 3: What about the program files\ folder which contains the binaries and some user settings which is present in the documents settings\user folder, will they be preserved at the time of OS upgrade? Answer 3: Yes.
Question 4: What is the common way of handling the OS upgrade? If some user installs program in Xp and then upgrades the OS to Vista? What is the option given to the user.? Which one MSFT recommends in case of OS upgrade
Question 5: Will the interface between MSI package and 'Add/Remove Programs' continue to be same (i.e., "Support information" that can be displayed in add/remove programs entry for this package, buttons like ADD, REMOVE, REPAIR, etc that are available in add/remove programs and after clicking these buttons the corresponding actions taken by MSI package, etc)? Answer 5: Yes. Look for two significant changes in Beta2. First, there’s a switch from ARP to Software Explorer which will provide a different view on the same data. Second, the introduction of UAP (formerly called LUA) may alter the user access to the feature formerly known as ARP. In the end literal interface (meaning the API between Software Explorer and MSI) will remain the same but the view on the data will change between ARP and Software Explorer.