diff --git a/install/user/mise.sh b/install/user/mise.sh
index b5c7884b..8106038e 100644
--- a/install/user/mise.sh
+++ b/install/user/mise.sh
@@ -1,3 +1,7 @@
+# Upgrades must not delete the version a running process is executing from:
+# mise up would prune the old install dir out from under a live session.
+mise settings set upgrade.auto_prune false
+
 omarchy-mise-install codex
 omarchy-mise-install claude
 omarchy-mise-install crush
diff --git a/migrations/1787215483.sh b/migrations/1787215483.sh
new file mode 100644
index 00000000..2e473ef0
--- /dev/null
+++ b/migrations/1787215483.sh
@@ -0,0 +1,3 @@
+echo "Stop mise upgrades from pruning versions still in use"
+
+mise settings set upgrade.auto_prune false