There is a MSI property that can be placed within the application package that allows the application setup to announce to Windows Installer that it wants to be installed “Per-User”.
Windows XP
The ALLUSERS MSI property can be set so that the application package will be run in the “Per-User” context. Both by the absence of the ALLUSERS property or the property is present but the value is set to NULL (ALLUSERS=”") will force the installation package to be run in the “Per-User” context.
Vista
On Vista, you could still force the installation package to be run as “Per-User” as we have discussed. Note that the user’s privileges are immaterial when running in the “Per-User” context – but once the decision is made that the install will be run in the “Per-User” context (By setting the ALLUSERS=”" or not having the property), the User rights issue makes no difference. But remember, the install starts but it WILL FAILif the user doesn’t have Admin rights and the install tries to write to any machine-wide resources.
If a user has Admin rights, but the install is run in the “Per-User” context, with the Admin rights, any accidental writing to machine-wide resources will be allowed.
Windows 7
On Windows 7, the ability to run as “Per-User” is constrained by the specifics of the package. Essentially these points are important for an application setup to be eligible for a “Per-User” installation context:
- All files are installed to Per-User folders, such as
- “C:\Documents and Settings\$User\Local Settings\Application Data” on WinXP
- “C:\Users\$User\AppData\Roaming” on Windows 7
- All Shortcuts and the Add/Remove Control Panel entry are only seen by that user
- All registry entries (Application data and registration) are made to HKEY_CURRENT_USER hive.
- No registry entries are made to machine-wide registry keys, such as HKEY_LOCAL_MACHINE or HKEY_CLASSES_ROOT hives
- The installation package cannot allow the user performing the installation package to select destination directories that are machine-wide, such as “c:\Program Files”
- All application binary file (EXE, DLL) need to be digitally signed to be allowed to be installed by “Per-User” for Windows 7.
On Windows 7, if any of the above constraints are not met, the package will be installed “Per-Machine” – this means that a “Per-User” will not be allowed!
