diff --git a/src/dll/posix.c b/src/dll/posix.c
index 4ae27355..f7a58f85 100644
--- a/src/dll/posix.c
+++ b/src/dll/posix.c
@@ -190,7 +190,7 @@ FSP_API NTSTATUS FspPosixMapUidToSid(UINT32 Uid, PSID *PSid)
                 Uid - 0x30000);
         }
     }
-    else if (0x100000 <= Uid && Uid < 0x300000)
+    else if (0x100000 <= Uid && Uid < 0xff000000)
     {
         if (0 != FspPrimaryDomainSid &&
             5 == FspPrimaryDomainSid->IdentifierAuthority.Value[5] &&