diff --git a/dlls/crypt32/tests/base64.c b/dlls/crypt32/tests/base64.c
index 965b3f8..9f648ac 100644
--- a/dlls/crypt32/tests/base64.c
+++ b/dlls/crypt32/tests/base64.c
@@ -273,14 +273,18 @@ static void decodeAndCompareBase64_A(LPCSTR toDecode, LPCSTR header,
         strcat(str, toDecode);
         if (trailer)
             strcat(str, trailer);
+        SetLastError(0xdeadbeef);
         ret = pCryptStringToBinaryA(str, 0, useFormat, NULL, &bufLen, NULL,
          NULL);
         /* expect failure with no header, and success with one */
         if (header)
             ok(ret, "CryptStringToBinaryA failed: %d\n", GetLastError());
         else
-            ok(!ret && GetLastError() == ERROR_INVALID_DATA,
-             "Expected !ret and last error ERROR_INVALID_DATA, got ret=%d, error=%d\n", ret, GetLastError());
+            ok((!ret && GetLastError() == ERROR_INVALID_DATA) ||
+             (useFormat == CRYPT_STRING_BASE64 && ret && GetLastError() == 0xdeadbeef) /* Vista */ ||
+             (useFormat == CRYPT_STRING_BASE64_ANY && ret && GetLastError() == ERROR_INVALID_DATA) /* Vista */,
+             "Expected !ret and last error ERROR_INVALID_DATA when converting \"%s\" with format %d, got ret=%d, error=%d\n",
+             str, useFormat, ret, GetLastError());
         if (ret)
         {
             buf = HeapAlloc(GetProcessHeap(), 0, bufLen);
@@ -290,7 +294,7 @@ static void decodeAndCompareBase64_A(LPCSTR toDecode, LPCSTR header,
 
                 ret = pCryptStringToBinaryA(str, 0, useFormat, buf, &bufLen,
                  &skipped, &usedFormat);
-                ok(skipped == strlen(garbage),
+                ok((skipped == strlen(garbage)) || (skipped == 0 && !header),
                  "Expected %d characters of \"%s\" skipped when trying format %08x, got %d (used format is %08x)\n",
                  lstrlenA(garbage), str, useFormat, skipped, usedFormat);
                 HeapFree(GetProcessHeap(), 0, buf);