How to lock or unlock transactions in SAP

There are some transactions that has to be locked in some sittuations, like se01 when system maintenance is going on like se01 or there are some critical transactions like scc5 that has to be locked... To lock such transactions we use sm01. After execution sm01 and selecting a particular transaction by entering in the search field





just check the field along the tcode and the transaction code will be locked. TO unlock the tcode just uncheck the check button