diff --git a/clang-tools-extra/clangd/index/remote/Client.cpp b/clang-tools-extra/clangd/index/remote/Client.cpp
--- a/clang-tools-extra/clangd/index/remote/Client.cpp
+++ b/clang-tools-extra/clangd/index/remote/Client.cpp
@@ -76,7 +76,9 @@
       : Stub(remote::SymbolIndex::NewStub(Channel)),
         ProtobufMarshaller(new Marshaller(/*RemoteIndexRoot=*/"",
                                           /*LocalIndexRoot=*/ProjectRoot)),
-        DeadlineWaitingTime(DeadlineTime) {}
+        DeadlineWaitingTime(DeadlineTime) {
+    assert(!ProjectRoot.empty());
+  }
 
   void lookup(const clangd::LookupRequest &Request,
               llvm::function_ref<void(const clangd::Symbol &)> Callback) const {
diff --git a/clang-tools-extra/clangd/index/remote/marshalling/Marshalling.cpp b/clang-tools-extra/clangd/index/remote/marshalling/Marshalling.cpp
--- a/clang-tools-extra/clangd/index/remote/marshalling/Marshalling.cpp
+++ b/clang-tools-extra/clangd/index/remote/marshalling/Marshalling.cpp
@@ -59,14 +59,16 @@
     assert(llvm::sys::path::is_absolute(RemoteIndexRoot));
     assert(RemoteIndexRoot ==
            llvm::sys::path::convert_to_slash(RemoteIndexRoot));
-    assert(RemoteIndexRoot.endswith(llvm::sys::path::get_separator()));
     this->RemoteIndexRoot = RemoteIndexRoot.str();
+    if (!RemoteIndexRoot.endswith(llvm::sys::path::get_separator()))
+      *this->RemoteIndexRoot += llvm::sys::path::get_separator();
   }
   if (!LocalIndexRoot.empty()) {
     assert(llvm::sys::path::is_absolute(LocalIndexRoot));
     assert(LocalIndexRoot == llvm::sys::path::convert_to_slash(LocalIndexRoot));
-    assert(LocalIndexRoot.endswith(llvm::sys::path::get_separator()));
     this->LocalIndexRoot = LocalIndexRoot.str();
+    if (!LocalIndexRoot.endswith(llvm::sys::path::get_separator()))
+      *this->LocalIndexRoot += llvm::sys::path::get_separator();
   }
   assert(!RemoteIndexRoot.empty() || !LocalIndexRoot.empty());
 }