We use wix Burn
to chain a list of packages that includes some executables and MSI with lots of custom actions and heavy operations.
<Chain>
<PackageGroupRef Id="NetFx48"/>
<PackageGroupRef Id="ThirdPartyEXE"/>
<PackageGroupRef Id="LongRunningMSI_1"/>
<PackageGroupRef Id="LongRunningMSI_2"/>
</Chain>
Just wandering:
No. Windows Installer does not support installing MSI packages in parallel.
The first MSI package would start installing. The subsequent installs would fail with an error that an install is in progress.
Burn will not purposefully fail by trying to execute multiple MSI packages at the same time, so... no?