When you create or modify a user, some files have a .Lock appended to them. They get appended to avoid any other change while these commands are used. At times, the operating system does not remove the .Lock from the file.

Example of files in lock state:

• /etc/passwd.lock
• /etc/shadow.lock
• /etc/group.lock
• /etc/gshadow.lock

These files are automatically removed when any of the following commands completes:

• seradd
• usermo
• groupadd