Wix toolset: complete cleanup after "disallowing uninstallation of component since another client exists"

It sounds like you need to uninstall the features (or whole products) that have installed your unwanted components. Windows Installer has an API for querying components, features and products. The WiX Toolset has incorporated a wrapper around the API called DTF. You can use it to query features by component.

So, break out your favorite .NET script runner (mine is LINQPad) and run a query. For example, to find out how to remove "candle.exe":

// using System.Linq;
// using Microsoft.Deployment.WindowsInstaller;

// <ref>"C:\Program Files (x86)\WiX Toolset v3.8\SDK\
         Microsoft.Deployment.WindowsInstaller.dll"</ref>

ComponentInstallation.AllComponents
    .Where(c=>c.State == InstallState.Local)
    .Where(c => c.Path.ToLowerInvariant().EndsWith(@"\candle.exe"))
    .SelectMany(c => c.ClientProducts
        .SelectMany(p => p.Features.Where(f => f.Usage.UseCount > 0)
            .Select(f => new {
                c.Path, 
                f.FeatureName,
                p.LocalPackage,
                p.UserSid, 
                p.ProductCode})))

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Then, run msiexec /x <ProductCode> to remove all the features of the products

or msiexec /i <LocalPackage> REMOVE=<FeatureName> to remove just the features that installed the component.

Even though this is a bit old link, however posting my findings which can be helpful to others, who are facing such same situation.

If you have found "Disallowing uninstallation of component: {Some GUID} since another client exists" in your log files, then the reason could be that your previous installations might still be referring to this component/GUID.

Moreover if you take a risk that you will try to remove the registry keys manually, you might even not find the GUID in regedit.

But few of these registries might be there and they may be hidden. In such case use RegSeeker tool http://www.hoverdesk.net/ , which can help finding the hidden registries. Be alert and cautious as you going to deal with registries.

Based on the GUID, get the name of the component from your solution/project and find it using the "Find in registry" option of this tool. Verify and remove only those entries which you think are not needed.

Admittedly, I came to know about this tool using below link

http://www.daviddeley.com/solutions/msiexec/index.htm

We recently had the case that one of our development machines couldn't remove all components on uninstallation. On other machines, however, the WiX setup worked as intended.

So, if you uninstalled incorrectly an earlier version of your product and getting the message Disallowing uninstallation of component: {GUID} since another client exists there is a high chance that you have orphan components lying around in your registry.

There is a much more elegant solution for deleting those hidden registry keys with PowerShell instead of using, as mentioned by others, a 3rd party application.

$productName = "Path\\YourProductName"  # this should basically match against your previous
# installation path. Make sure that you don't mess with other components used 
# by any other MSI package

$components = Get-ChildItem -Path HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Components\
$count = 0

foreach ($c in $components) 
{
    foreach($p in $c.Property)
    {
        $propValue = (Get-ItemProperty "Registry::$($c.Name)" -Name "$($p)")."$($p)"
        if ($propValue -match $productName) 
        {
            Write-Output $propValue
            $count++
            Remove-Item "Registry::$($c.Name)" -Recurse
        }
    }
}

Write-Host "$($count) key(s) removed"

If you want to get a more detailed explanation about the cause of the message disallowing uninstallation... take a look here.