diff --git a/README.md b/README.md
index 02c2e7d..cbe27f2 100644
--- a/README.md
+++ b/README.md
@@ -63,6 +63,8 @@ In `~/nostalgia_data/videos_watched.jsonl` the data for events on HTML5 video el
 
 On Linux (systemctl based):
 
+Ensure you've activated the same virtualenv, or use the same python version for sysdm as nostalgia_chrome. Then:
+
     pip install sysdm
     sysdm create "nostalgia_chrome run_server" --extensions ""