From last one month started working on OpenERP. While customizing code daily facing one or the other issue. So thought of keeping all of them at one place with solutions for future use and may be can help someone else as well : 1) AttributeError: 'NoneType' object has no attribute '_columns' Solution : Problem is with your __openerp__.py file. Check depends attribute. Reference Links : http://stackoverflow.com/questions/10565288/attributeerror-nonetype-object-has-no-attribute-columns http://forum.openerp.com/forum/topic24199.html 2) Openerp : new module is not showing into module list? Solution : If you have developed a new module and it's in the addons folder but still not showing in the module list than follow following steps : a) Restart OpenERP server by using command : ./openerp-server --addons-path=XXXX/XXXXXXX/addons/ (path of addons directory) b) Go to the browser and open localhost:8069 o r 127.0.0.1:8069 c) Login into OpenERP; Go t