diff --git a/dlls/opcservices/factory.c b/dlls/opcservices/factory.c
index 2ecd5adca9d..9036141495e 100644
--- a/dlls/opcservices/factory.c
+++ b/dlls/opcservices/factory.c
@@ -312,6 +312,9 @@ static HRESULT WINAPI opc_factory_CreatePackageRootUri(IOpcFactory *iface, IOpcU
 {
     TRACE("iface %p, uri %p.\n", iface, uri);
 
+    if (!uri)
+        return E_POINTER;
+
     return opc_root_uri_create(uri);
 }
 
diff --git a/dlls/opcservices/tests/opcservices.c b/dlls/opcservices/tests/opcservices.c
index 63932fe832e..84a8c12dc9d 100644
--- a/dlls/opcservices/tests/opcservices.c
+++ b/dlls/opcservices/tests/opcservices.c
@@ -41,16 +41,18 @@ static void test_package(void)
     static const WCHAR typeW[] = {'t','y','p','e','/','s','u','b','t','y','p','e',0};
     static const WCHAR targetW[] = {'t','a','r','g','e','t',0};
     static const WCHAR uriW[] = {'/','u','r','i',0};
+    static const WCHAR rootW[] = {'/',0};
     IOpcRelationshipSet *relset, *relset2;
     IOpcPartSet *partset, *partset2;
     IOpcRelationship *rel;
     IOpcPartUri *part_uri;
     IOpcFactory *factory;
     IOpcPackage *package;
-    IOpcUri *source_uri;
     IUri *target_uri;
     IOpcPart *part;
+    IOpcUri *uri;
     HRESULT hr;
+    BSTR str;
     BOOL ret;
 
     factory = create_factory();
@@ -93,11 +95,11 @@ static void test_package(void)
     hr = IOpcRelationshipSet_CreateRelationship(relset, NULL, typeW, target_uri, OPC_URI_TARGET_MODE_INTERNAL, &rel);
     ok(SUCCEEDED(hr), "Failed to create relationship, hr %#x.\n", hr);
 
-    hr = IOpcRelationship_GetSourceUri(rel, &source_uri);
+    hr = IOpcRelationship_GetSourceUri(rel, &uri);
     ok(SUCCEEDED(hr), "Failed to get source uri, hr %#x.\n", hr);
-    ok(source_uri == (IOpcUri *)part_uri, "Unexpected source uri.\n");
+    ok(uri == (IOpcUri *)part_uri, "Unexpected source uri.\n");
 
-    IOpcUri_Release(source_uri);
+    IOpcUri_Release(uri);
 
     IOpcRelationship_Release(rel);
     IUri_Release(target_uri);
@@ -126,6 +128,17 @@ todo_wine {
 
     IOpcPackage_Release(package);
 
+    /* Root uri */
+    hr = IOpcFactory_CreatePackageRootUri(factory, NULL);
+    ok(hr == E_POINTER, "Unexpected hr %#x.\n", hr);
+    hr = IOpcFactory_CreatePackageRootUri(factory, &uri);
+    ok(SUCCEEDED(hr), "Failed to create root uri, hr %#x.\n", hr);
+    hr = IOpcUri_GetRawUri(uri, &str);
+    ok(SUCCEEDED(hr), "Failed to get raw uri, hr %#x.\n", hr);
+    ok(!lstrcmpW(str, rootW), "Unexpected uri %s.\n", wine_dbgstr_w(str));
+    SysFreeString(str);
+    IOpcUri_Release(uri);
+
     IOpcFactory_Release(factory);
 }
 
diff --git a/dlls/opcservices/uri.c b/dlls/opcservices/uri.c
index 0c5afa9b299..e461ebaa587 100644
--- a/dlls/opcservices/uri.c
+++ b/dlls/opcservices/uri.c
@@ -552,6 +552,8 @@ HRESULT opc_root_uri_create(IOpcUri **out)
     HRESULT hr;
     IUri *uri;
 
+    *out = NULL;
+
     if (!(obj = heap_alloc_zero(sizeof(*obj))))
         return E_OUTOFMEMORY;