diff --git a/clang-tools-extra/clangd/index/StdLib.cpp b/clang-tools-extra/clangd/index/StdLib.cpp
--- a/clang-tools-extra/clangd/index/StdLib.cpp
+++ b/clang-tools-extra/clangd/index/StdLib.cpp
@@ -224,10 +224,11 @@
   IgnoreDiagnostics IgnoreDiags;
   // CompilerInvocation is taken from elsewhere, and may map a dirty buffer.
   CI->getPreprocessorOpts().clearRemappedFiles();
+  std::string CWD = CI->getFileSystemOpts().WorkingDir;
   auto Clang = prepareCompilerInstance(
       std::move(CI), /*Preamble=*/nullptr,
       llvm::MemoryBuffer::getMemBuffer(HeaderSources, Input.getFile()),
-      TFS.view(/*CWD=*/std::nullopt), IgnoreDiags);
+      TFS.view(CWD), IgnoreDiags);
   if (!Clang) {
     elog("Standard Library Index: Couldn't build compiler instance");
     return Symbols;