Well for last few days I was having problem on mu ubuntu system. When I am logged in as root I press some text and press tab it give me suggestion of files and folder but for user auto completion was not working but any how after long search I got the result and solved it.
Well you need to login with root and open this file
Note: open file Depends on your editor software available on your ubuntu
Search your user
Replace with this
Now login with your user auto complete will work.