diff --git a/dlls/shlwapi/tests/path.c b/dlls/shlwapi/tests/path.c
index 41f9f1407d2..c91e99ffc95 100644
--- a/dlls/shlwapi/tests/path.c
+++ b/dlls/shlwapi/tests/path.c
@@ -198,7 +198,10 @@ const TEST_URL_COMBINE TEST_COMBINE[] = {
     {"file:///C:\\dir\\file.txt", "test.txt", 0, S_OK, "file:///C:/dir/test.txt"},
     {"http://www.winehq.org/test/", "test%20file.txt", 0, S_OK, "http://www.winehq.org/test/test%20file.txt"},
     {"http://www.winehq.org/test/", "test%20file.txt", URL_FILE_USE_PATHURL, S_OK, "http://www.winehq.org/test/test%20file.txt"},
-    {"http://www.winehq.org%2ftest/", "test%20file.txt", URL_FILE_USE_PATHURL, S_OK, "http://www.winehq.org%2ftest/test%20file.txt"}
+    {"http://www.winehq.org%2ftest/", "test%20file.txt", URL_FILE_USE_PATHURL, S_OK, "http://www.winehq.org%2ftest/test%20file.txt"},
+    {"xxx:@MSITStore:file.chm/file.html", "dir/file", 0, S_OK, "xxx:dir/file"},
+    {"mk:@MSITStore:file.chm::/file.html", "/dir/file", 0, S_OK, "mk:@MSITStore:file.chm::/dir/file"},
+    {"mk:@MSITStore:file.chm::/file.html", "mk:@MSITStore:file.chm::/dir/file", 0, S_OK, "mk:@MSITStore:file.chm::/dir/file"},
 };
 
 struct {
diff --git a/dlls/shlwapi/url.c b/dlls/shlwapi/url.c
index 6c88e919c88..50e608a1015 100644
--- a/dlls/shlwapi/url.c
+++ b/dlls/shlwapi/url.c
@@ -629,6 +629,22 @@ HRESULT WINAPI UrlCombineW(LPCWSTR pszBase, LPCWSTR pszRelative,
 	process_case = 1;
     }
     else do {
+        /* mk is a special case */
+        if(base.nScheme == URL_SCHEME_MK) {
+            static const WCHAR wsz[] = {':',':',0};
+
+            WCHAR *ptr = strstrW(base.pszSuffix, wsz);
+            if(ptr) {
+                int delta;
+
+                ptr += 2;
+                delta = ptr-base.pszSuffix;
+                base.cchProtocol += delta;
+                base.pszSuffix += delta;
+                base.cchSuffix -= delta;
+            }
+        }
+
 	/* get size of location field (if it exists) */
 	work = (LPWSTR)base.pszSuffix;
 	sizeloc = 0;