How to completly remove a virtual disk created?

Question

I'm experiencing the same problem seen on this question, i have a lot of vhdx disk listed that seens that are not being properly "removed", even after detaching and deleting them.

There's no answer on the mentioned question as the OP "solved" the issue by rebooting the system.

I'm able to find these "ghost" disks with a call to QueryVDisks, pVDisk->Open works on them, but im not sure what the proper way to completly "release" the disk, i tried calling dettach again but it result in the error:

0x80042935

VDS_E_VD_ALREADY_DETACHED

What is the proper way to completly remove a virtual disk created?

void detachVirtualDisk(const std::wstring& diskPath)
{
    CComPtr<IVdsService>       pSvc;
    CComPtr<IVdsServiceLoader> pLoader;
    CComQIPtr<IVdsVdProvider>  pProv;
    hr = CoInitializeSecurity(
        NULL,
        -1,                          // COM authentication
        NULL,                        // Authentication services
        NULL,                        // Reserved
        RPC_C_AUTHN_LEVEL_DEFAULT,   // Default authentication 
        RPC_C_IMP_LEVEL_IMPERSONATE, // Default Impersonation  
        NULL,                        // Authentication info
        EOAC_NONE,                   // Additional capabilities 
        NULL                         // Reserved
    );
    
    hr = pLoader.CoCreateInstance(CLSID_VdsLoader, nullptr, CLSCTX_LOCAL_SERVER);
    if (SUCCEEDED(hr))
    {
        hr = pLoader->LoadService(nullptr, &pSvc);
        pLoader.Release();
    }
    
    if (!pSvc)
    {
        wprintf_s(L"Could not connect to VDS, error 0x%X\n", hr);
        return;
    }

    pSvc->WaitForServiceReady();

    CComPtr<IEnumVdsObject> pEnum;
    hr = E_FAIL;
    hr = pSvc->QueryProviders(VDS_QUERY_VIRTUALDISK_PROVIDERS, &pEnum);
    if (SUCCEEDED(hr))
    {
        ULONG cFetched = 0;
        for (CComPtr<IUnknown> pUnk; pEnum->Next(1, &pUnk, &cFetched) == S_OK; pUnk.Release())
        {
            VDS_PROVIDER_PROP vpp{};
            CComQIPtr<IVdsProvider> provider(pUnk);

            hr = provider->GetProperties(&vpp);
            if (SUCCEEDED(hr))
            {
                CoTaskMemFree(vpp.pwszName);
                CoTaskMemFree(vpp.pwszVersion);
                if (IsEqualGUID(VDS_VIRTUAL_DISK_PROVIDER, vpp.id))
                {
                    hr = provider->QueryInterface(IID_PPV_ARGS(&pProv));
                    break;
                }
            }
        }
    }

    if (FAILED(hr) || !pProv)
    {
        wprintf_s(L"Failed to obtain IVdsVdProvider interface, error was 0x%X\n", hr);
        return;
    }

    // Enumerate virtual disks
    CComPtr<IEnumVdsObject> pDiskEnum;
    hr = pProv->QueryVDisks(&pDiskEnum);
    if (FAILED(hr))
    {
        wprintf_s(L"Failed to enumerate virtual disks, error was 0x%X\n", hr);
        return;
    }


    ULONG cFetched = 0;
    for (CComPtr<IUnknown> pUnk; pDiskEnum->Next(1, &pUnk, &cFetched) == S_OK; pUnk.Release())
    {
        CComQIPtr<IVdsVDisk> pVDisk(pUnk);
        if (!pVDisk)
            continue;

        VDS_VDISK_PROPERTIES props{};
        hr = pVDisk->GetProperties(&props);
        if (FAILED(hr) || props.pPath != diskPath)
            continue;

        CComPtr<IVdsOpenVDisk> pVdsOpenVDisk;    
        hr = pVDisk->Open(VIRTUAL_DISK_ACCESS_ALL, OPEN_VIRTUAL_DISK_FLAG_NONE, OPEN_VIRTUAL_DISK_RW_DEPTH_DEFAULT, &pVdsOpenVDisk);
        if (FAILED(hr) || !pVdsOpenVDisk)
			continue;

        hr = pVdsOpenVDisk->Detach(DETACH_VIRTUAL_DISK_FLAG_NONE, 0);
    }
}

Answer 1

Does this issue reproduce at your side when you creates vhdx disks?

I reproduced your observation in a separate test. The issue seems to be related to a cache maintained by the Virtual Disk Service (vds).Rebooting is not necessary. Stopping the vds service is sufficient is sufficient to clear the cache.