diff --git a/clang-tools-extra/clangd/HeaderSourceSwitch.cpp b/clang-tools-extra/clangd/HeaderSourceSwitch.cpp
--- a/clang-tools-extra/clangd/HeaderSourceSwitch.cpp
+++ b/clang-tools-extra/clangd/HeaderSourceSwitch.cpp
@@ -11,6 +11,7 @@
 #include "SourceCode.h"
 #include "index/SymbolCollector.h"
 #include "support/Logger.h"
+#include "support/Path.h"
 #include "clang/AST/Decl.h"
 
 namespace clang {
@@ -82,7 +83,7 @@
   llvm::StringMap<int> Candidates; // Target path => score.
   auto AwardTarget = [&](const char *TargetURI) {
     if (auto TargetPath = URI::resolve(TargetURI, OriginalFile)) {
-      if (*TargetPath != OriginalFile) // exclude the original file.
+      if (!pathEqual(*TargetPath, OriginalFile)) // exclude the original file.
         ++Candidates[*TargetPath];
     } else {
       elog("Failed to resolve URI {0}: {1}", TargetURI, TargetPath.takeError());
diff --git a/clang-tools-extra/clangd/unittests/TestFS.cpp b/clang-tools-extra/clangd/unittests/TestFS.cpp
--- a/clang-tools-extra/clangd/unittests/TestFS.cpp
+++ b/clang-tools-extra/clangd/unittests/TestFS.cpp
@@ -73,7 +73,11 @@
 
 const char *testRoot() {
 #ifdef _WIN32
-  return "C:\\clangd-test";
+  // On windows paths are insensitive, simulate that behaviour by toggling
+  // capitalization for drive-letter on each call.
+  static bool CallParity = false;
+  CallParity = !CallParity;
+  return CallParity ? "C:\\clangd-test" : "c:\\clangd-test";
 #else
   return "/clangd-test";
 #endif