I have the problem that a specific user can't use usb sticks any more. they are not mounted automatically any more. For some weird reason I changed the numeric userid and groupid of this user (actually to solve some problems with a NAS).

I saved the home directory of the user in question and deleted the user. When I create a new user with the same numeric uid but a new username, it works. When I create a new user with the same numeric and username, it doesn't work ...

using Ubuntu 14.04

thankful for any hint!


When you changed the userid and groupid of the user you essentially "made" a new user without adding that user to the groups that the original was in. Type


to see what groups a given user is in. By default on Trusty I am in the following groups:

eagle adm cdrom sudo dip plugdev lpadmin sambashare

Your problem user will likely be in no groups or only the user's personal group. To add more groups you will need to use the usermod command as root. In order to allow usb drives to be used you will need to execute

usermod -Ga plugdev login_name

where login_name is the name of your user. If you want to add all the default groups, execute

usermod -Ga adm,cdrom,dip,plugdev,lpadmin,sambashare login_name

If your user was able to use the sudo command, also add sudo to the above list.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.