diff --git a/dlls/dpvoice/client.c b/dlls/dpvoice/client.c
index bdae160b20c..7f6cf4ad75d 100644
--- a/dlls/dpvoice/client.c
+++ b/dlls/dpvoice/client.c
@@ -286,7 +286,8 @@ static HRESULT WINAPI dpvtest_CheckAudioSetup(IDirectPlayVoiceTest *iface, const
                      HWND hwndParent, DWORD dwFlags)
 {
     IDirectPlayVoiceTestImpl *This = impl_from_IDirectPlayVoiceTest(iface);
-    FIXME("%p %p %p %p %d\n", This, pguidPlaybackDevice, pguidCaptureDevice, hwndParent, dwFlags);
+    FIXME("%p %s %s %p %d\n", This, debugstr_guid(pguidPlaybackDevice),
+            debugstr_guid(pguidCaptureDevice), hwndParent, dwFlags);
     return E_NOTIMPL;
 }
 
diff --git a/dlls/dpvoice/main.c b/dlls/dpvoice/main.c
index aab0859e282..3a74e013e56 100644
--- a/dlls/dpvoice/main.c
+++ b/dlls/dpvoice/main.c
@@ -102,7 +102,7 @@ static IClassFactoryImpl DPVOICE_CFS[] =
 
 HRESULT WINAPI DirectPlayVoiceCreate(LPCGUID pIID, void **ppvInterface)
 {
-    FIXME("(%p, %p) stub\n", pIID, ppvInterface);
+    FIXME("(%s, %p) stub\n", debugstr_guid(pIID), ppvInterface);
     return E_NOTIMPL;
 }