diff --git a/ExistingProjects/ERP5.mdwn b/ExistingProjects/ERP5.mdwn
index 1afd38f0b74e605662c7c02c89f77d2961ee80eb..aac8be19717c9ffa313c9d3fdd2840e4cea121ed 100644
--- a/ExistingProjects/ERP5.mdwn
+++ b/ExistingProjects/ERP5.mdwn
@@ -28,6 +28,9 @@
 ### Negative
 
 - Community: The mailing lists are not very active, see <http://mail.tiolive.com/pipermail/erp5-users/>, <http://mail.tiolive.com/pipermail/erp5-dev/>
+- Take time to study(important to understand its design(Unified Business Model))
+- Installation is not simple
+- Need to read source code and need some experience.
 
 ### Comments