diff --git a/src/os.cpp b/src/os.cpp
index d335d8d218..c93e2887b7 100644
--- a/src/os.cpp
+++ b/src/os.cpp
@@ -1334,7 +1334,7 @@ com_done:;
 
 int os_get_win32_ucrt_lib_path(ZigWindowsSDK *sdk, Buf* output_buf, ZigLLVM_ArchType platform_type) {
 #if defined(ZIG_OS_WINDOWS)
-    if (buf_len(sdk->path10) == 0 || buf_len(sdk->version10) == 0) {
+    if (buf_len(&sdk->path10) == 0 || buf_len(&sdk->version10) == 0) {
         return ErrorFileNotFound;
     }
     buf_resize(output_buf, 0);