diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -262,6 +262,9 @@
         ec = retryMb.getError();
         if (!ec)
           mb = std::move(*retryMb);
+      } else {
+        // We've already handled this file.
+        return;
       }
     }
     if (ec) {
diff --git a/lld/test/COFF/winsysroot.test b/lld/test/COFF/winsysroot.test
--- a/lld/test/COFF/winsysroot.test
+++ b/lld/test/COFF/winsysroot.test
@@ -26,6 +26,10 @@
 # RUN: lld-link %t.obj /winsysroot:%t.dir/sysroot \
 # RUN:          std32.lib /entry:main
 
+Check that passing a lib from /winsysroot twice is ok
+# RUN: lld-link %p/Inputs/hello64.obj /winsysroot:%t.dir/sysroot \
+# RUN:          std64.lib std64.lib /entry:main
+
 If winsysroot lib appears before we can detect arch we don't find it
 # RUN: not lld-link std64.lib %p/Inputs/hello64.obj /winsysroot:%t.dir/sysroot \
 # RUN:          /entry:main