diff --git a/src/syncterm/SyncTERM.vcxproj b/src/syncterm/SyncTERM.vcxproj
index fe5ed0ddf9383b67248c9d5283722e830b0a5aaf..ca8e9e2bc5ddecac828ba28df4014aee2b0deebe 100644
--- a/src/syncterm/SyncTERM.vcxproj
+++ b/src/syncterm/SyncTERM.vcxproj
@@ -80,6 +80,7 @@
       <AdditionalIncludeDirectories>%(AdditionalIncludeDirectories);..\sbbs3</AdditionalIncludeDirectories>
       <RuntimeLibrary>MultiThreadedDebug</RuntimeLibrary>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/experimental:c11atomics %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
@@ -99,6 +100,7 @@
       <AdditionalIncludeDirectories>%(AdditionalIncludeDirectories);..\sbbs3;</AdditionalIncludeDirectories>
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
+      <AdditionalOptions>/experimental:c11atomics %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Windows</SubSystem>
diff --git a/src/syncterm/telnets.c b/src/syncterm/telnets.c
index 69288a0ce2451bfc96638c42b4f3c4c3b6676249..875f5d85c14c2091099fc6a487eb62cb2e7f6cc6 100644
--- a/src/syncterm/telnets.c
+++ b/src/syncterm/telnets.c
@@ -1,5 +1,6 @@
 /* Copyright (C), 2007 by Stephen Hurd */
 
+#ifndef _MSC_VER
 #if defined(__STDC_NO_ATOMICS__)
 #error Support for stdatomic.h is required.
 #endif