user exists

Hi,
I just converted my HDD from ext3 to ext4 filesystem. The data content was backup before this.
After NAS reboot I had to re-define shares and users which worked fine with only one exeption:
A creation of user "gast" wasn't possible. Error message : can not add user, username already exists
A check of the existing user base via SSL does not show the user "gast".
What is wrong ?
P.S. User "guest" is possible but I want it in german ;)
I just converted my HDD from ext3 to ext4 filesystem. The data content was backup before this.
After NAS reboot I had to re-define shares and users which worked fine with only one exeption:
A creation of user "gast" wasn't possible. Error message : can not add user, username already exists
A check of the existing user base via SSL does not show the user "gast".
What is wrong ?
P.S. User "guest" is possible but I want it in german ;)