keep all users out of a transaction?

Locking R/3 Transactions

1.               Log on to any client in the appropriate SAP system.

2.               Go to transaction SM01.

3.               On the Transaction Code: Lock/Unlock screen, you will see an empty box at the very bottom of the screen.  Type in the transaction code you want to lock and press Enter.

4.               The transaction code to be locked should appear at the top of the transaction list.  Place a √ in the □ to the left of the transaction to be locked by pressing Space.  Press Enter.

5.               The transaction is now locked.  You may now leave the SM01 transaction.