[Samba] Samba lost group memberships

[Rowland Penny]

On Wed, 12 Nov 2025 10:29:34 +0100
"Pluess, Tobias via samba" <samba at lists.samba.org> wrote:

> Hello list,
> since today, I encounter this interesting problem.
> 
> System: Debian 13 with smb Version 4.22.4-Debian-4.22.4+dfsg-1~deb13u1
> I am using the "ad" backend.
> 
> It works in the sense that the IDs of users can be retrieved:
> 
> id <username> returns a valid ID and works. However it takes long
> time for the command to complete.
> I get something like this
> 
> # id <myusername>
> uid=5486(tp18v123) gid=1080
> groups=1080,513,8252,103474,8319,103464,102704,1905,103074,8324,100494,10374,5505,9295,7646,10375,6022,8735,5556,8656,9158,5855,2080,8255,2089,6020,102789,104387,8627,9291,8483,7682,10456,6614,8386,10000001(BUILTIN\users)
> 
> so all the groups vanished and only their group IDs are visible.
> 
> I can use
> 
> # getent passwd <username>
> and some sensible info is retrieved, it seems to recognise the
> account, but also here, the group memberships are gone and replaced
> just by their ID.
> 
> # getent group
> 
> gives no info at all. If I try to manually mount a share with
> 
> mount -t cifs //server/share /mnt/temp -o
> vers=3,user=<myusername>,domain=<domain>
> 
> it appears that the access is denied. I see in the log files errors
> 
> check_account: Failed to convert SID
> S-1-5-21-1442852101-4018948630-3783845812-142435 to a UID
> 
> and
> 
> parse_dfs_path_strict: Hostname is not ours.
> 
> Where should I start looking?

First I suggest you post your smb.conf file.

Second, has anything changed ? Have you installed any updates ?

Rowland