msiexec /i Setup.msi /qb ALLUSERS=1
Occasionally though, you'll run into problems. We had an app that seemed to install successfully. However, each time the app was run, the MSI ran through some checks and appeared to try to repair the app.
After a bit of digging it turned out that the problem was being caused by an advertised shortcut. Each time the app was run, the advertised shortcut kicked off an auto-repair, even though the app was installed successfully. The quick (and probably nasty solution) was to install the app without the advertised shortcut
msiexec /i Setup.msi /qb ALLUSERS=1 DISABLEADVTSHORTCUTS=1
In situations like this it's probably better to return to the vendor and ask for a working MSI, or to use a tool like Orca to discover what is causing the auto-repair to kick in.