If you were ever wondering how to properly read the list of installed MSI software, then two popular choices are available:
- Querying uninstall registry keys (
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall), filtering out-non MSI entries and outputting the rest - Using
Win32_Productfrom WMI
They both have their pros and cons. Querying registry is straightforward on its own, but requires awkward manipulations and accessing the data which is actually backing the Add/Remove Applet, not necessarily the Windows Installer API which uses its own complex registration. Additionally it may not work correctly with different installation context (user/machine) and you may have to query two places to get both x86 and x64 installations on a x64 system.
On the other hand, while WMI query is also pretty straightforward (see https://msdn.microsoft.com/en-us/library/aa394378(v=VS.85).aspx?f=255&MSPPError=-2147217396), it has a really big drawback. Running it is painfully slow, because Windows Installer checks integrity of each entry and triggers appropriate action (for example repair) if necessary.
So to have a solution which is both fast, reliable and without any side-effects, you may go for a third solution which is more complex, but once setup can be reused not only for querying but for a whole management of MSI-based installations. And so this blog today will be about P/invoking native msi.dll to get results returned by the true Windows Installer API.
This post may be too technical if you have never programmed in C/C++ or C#. If you just want the results without understanding how to implement them on your own, scroll to the bottom, the full content of the PowerShell script is there.
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