We can use SU01 to lock large number of users,
  • Go to SU10 tcode
  • Enter the Usernames needs to be locked(it can up to 21 users)
  • Use option Authorization data If you want to select more than 21 users
  • After selecting users hit enter so you can came to how may users are active in the box
  • Now click Lock button in the Icons list to lock the users.

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