Index: COFF/PDB.cpp
===================================================================
--- COFF/PDB.cpp
+++ COFF/PDB.cpp
@@ -351,6 +351,12 @@
 
 static Expected<std::unique_ptr<pdb::NativeSession>>
 tryToLoadPDB(const GUID &GuidFromObj, StringRef TSPath) {
+  // Ensure the file exists before anything else. We want to return ENOENT,
+  // "file not found", even if the path points to a removable device (in which
+  // case the return message would be EAGAIN, "resource unavailable try again")
+  if (!llvm::sys::fs::exists(TSPath))
+    return errorCodeToError(std::error_code(ENOENT, std::generic_category()));
+
   ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr = MemoryBuffer::getFile(
       TSPath, /*FileSize=*/-1, /*RequiresNullTerminator=*/false);
   if (!MBOrErr)