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I've been trying to set this up, but I can't find a solution. It's neccessary, because the machine Ubuntu is on is a Macbook and needs to have access to the files of the Mac user. Is there any way to get this to work?

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How about usermod -u UID username – Achu Nov 2 '12 at 18:55
No you don't want to renumber the user. this would simply remove it from LightDMs display as well. What you are looking for is some parameter of the lightDM configuration in your /etc or maybe /etc/xorg directory. I don't have lightdm installed currently, so I can't tell you which one. – Paul Hänsch Nov 2 '12 at 18:59
Oh wait, I think what Achu meant was modifying the MacOS user. This would probably be the cleanest solution. Don't forget to chown all the files of the Mac-User afterwards, so they belong to the new UserID. – Paul Hänsch Nov 2 '12 at 19:01
Ah, thanks, I didn't think of doing that. I'll try that instead then, since it appears to be the cleanest. Is there any easy way to chown all the files on the Mac to the new UID? – DoDoGo Nov 2 '12 at 19:03
Hm, that's not the command on OSX, any other ideas? – DoDoGo Nov 2 '12 at 19:43
up vote 7 down vote accepted

Lightdm has the config file /etc/lightdm/users.conf which you can edit to set a minimum UID. The default is 500. It also sets hidden users and certain shells that if a user has are hidden. Try editing that file and restarting lightdm.

hidden-users=nobody nobody4 noaccess
hidden-shells=/bin/false /usr/sbin/nologin
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Thanks, this solves it! But must have been default is 1000, as I set the UID to 502 and the user disappered. – DoDoGo Nov 10 '12 at 18:37

You will probably also want to change the defaults for adduser & useradd, to create new users with UID starting at 500.

Two files need change, as:


# Min/max values for automatic uid selection in useradd
UID_MIN            500
UID_MAX          60000
# System accounts
#SYS_UID_MIN       100
#SYS_UID_MAX       499
# Min/max values for automatic gid selection in groupadd
GID_MIN            500
GID_MAX          60000
# System accounts
#SYS_GID_MIN       100
#SYS_GID_MAX       499


# package, may assume that UIDs less than 100 are unallocated.


# FIRST_[GU]ID to LAST_[GU]ID inclusive is the range of UIDs of dynamically
# allocated user accounts/groups.

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Why so? The newly created users are in no way guaranteed to match the new ones on the Mac, and either way it's a single-user laptop. Thanks though, I'll remember this for future use, and perhaps it'll help some other people when they find this question and answers. – DoDoGo Nov 11 '12 at 21:47
+1 Thanks! My /etc/lightdm/users.conf had minimum-uid=500 but still would not show users whose uid was less than 1000. – copper.hat Sep 29 '13 at 21:15

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