Add list import warning
diff --git a/source/markdown/docs/IMPORTING.md b/source/markdown/docs/IMPORTING.md
index 465cd28..a54de39 100644
--- a/source/markdown/docs/IMPORTING.md
+++ b/source/markdown/docs/IMPORTING.md
@@ -11,6 +11,12 @@
## Importing from mod_mbox
+### Warning ###
+
+Pony Mail relies on the mail headers to determine the correct list name for each email.
+
+If in any doubt, import a single list at a time and use the --lid flag to specify the correct list name.
+
### Importing a single domain
Provided you have the main mod_mbox page at https://your.tld/mod_mbox/ and your (sub)domain resources at
https://your.tld/mod_mbox/$list-yourdomain/, you can import all lists from that domain using:
