diff --git a/src/common/progress.hpp b/src/common/progress.hpp
index 7e5a0bca..a88762ef 100644
--- a/src/common/progress.hpp
+++ b/src/common/progress.hpp
@@ -79,7 +79,7 @@ class ProgressMeter {
         //std::cerr << input_seconds << " seconds is " << days << " days, " << hours << " hours, " << minutes << " minutes, and " << seconds << " seconds." << std::endl;
     }
     void increment(const uint64_t& incr) {
-        completed += incr;
+        completed.fetch_add(incr, std::memory_order_relaxed);
     }
 };