diff --git a/src/docs/user/installation_guide.diviner b/src/docs/user/installation_guide.diviner
--- a/src/docs/user/installation_guide.diviner
+++ b/src/docs/user/installation_guide.diviner
@@ -134,6 +134,11 @@
   somewhere/ $ git clone https://we.phorge.it/source/arcanist.git
   somewhere/ $ git clone https://we.phorge.it/source/phorge.git
 
+To avoid errors in recent git versions, mark Arcanist and Phorge as safe:
+
+  $ git config --system --add safe.directory somewhere/arcanist
+  $ git config --system --add safe.directory somewhere/phorge
+
 Next Steps
 ==========