diff --git a/toolkit/system/windowsproxy/nsWindowsSystemProxySettings.cpp b/toolkit/system/windowsproxy/nsWindowsSystemProxySettings.cpp
index 7d57ac7ba3a8..029192658125 100644
--- a/toolkit/system/windowsproxy/nsWindowsSystemProxySettings.cpp
+++ b/toolkit/system/windowsproxy/nsWindowsSystemProxySettings.cpp
@@ -91,12 +91,12 @@ static nsresult ReadInternetOption(uint32_t aOption, uint32_t& aFlags,
         }
         options[0].dwOption = INTERNET_PER_CONN_FLAGS;
         size = sizeof(INTERNET_PER_CONN_OPTION_LISTW);
-        __try {
+        MOZ_SEH_TRY {
             if (!InternetQueryOptionW(NULL, INTERNET_OPTION_PER_CONNECTION_OPTION,
                                       &list, &size)) {
                 return NS_ERROR_FAILURE;
             }
-        } __except (EXCEPTION_EXECUTE_HANDLER) {
+        } MOZ_SEH_EXCEPT (EXCEPTION_EXECUTE_HANDLER) {
             return NS_ERROR_FAILURE;
         }
     }