Odoo is the world's easiest all-in-one management software. It includes hundreds of business apps:
CRM | e-Commerce | Accounting | Inventory | PoS | Project management | MRP | etc.
Because I needed it, I did it.
Here is TG_Erp_Status Module, that allows to put openERP in Maintenance Mode.
When in Maintenance mode, only Administrator can use OpenERP. A message is displayed for all other users.
I use it to make updates, and to be sure no user is working during the update. Easy to install, easy to use. Just create Maintenance messages, and maintenances mode. Select proper Mode as "Current ERP Status" (Ie : opened, or closed)
Some screenshots :
This is the message that is displayed when in Maintenance mode for all users :
ERP Status messages :
ERP Status modes :
Menu is in Configuration > Configuration :
When in Maintenance Mode, just turn it back to "Open" mode to allow users to use OpenERP again.
Download link : tg_erp_status_1.1.0.zip
Of course, you can tune Css, or change anything as well to fit your needs.
EDIT : 04/04/2014 :
I added a new feature :
An internal status frame to recall the admin that the ERP is closed (to not forget to reopen).
Module is updated and download link updated too.