· Never delete “obsolete” licenses if you do not have an active license. The system needs this information to decide whether a temporary license can be installed (see Installing Temporary SAP Licenses in the Prerequisites section).
· You should not delete the currently active license (this is the one highlighted in transaction SLICENSE). If you want to do so, you should first install a (temporary) license so that other users can log onto the system.
· The status of a license is not checked when a license is deleted. In particular, there is no check to establish whether you are deleting a license that is currently in use. Once you delete a valid license that is currently in use, no additional users will be able to log onto the system from this point on (exception: user sap*). Users who are currently logged on, however, can continue to work.
If, by mistake, you delete a valid license that is currently in use, you can reinstall it at any time. See transaction SLICENSE. The prerequisite is that you have kept your license key.
· Old licenses that are no longer used do not affect the operation of your SAP system. Nevertheless, it is advisable to delete licenses that are no longer used (performance optimization during the license check).
You can recognize temporary licenses that are based on old license keys by the characteristic, CUSTOMER KEY = TEMPLICENSE. You can recognize temporary licenses that are based on new license keys in the table Licenses in the Database in column Type (Perm or Temp). Deleting temporary licenses does not mean that you can install further temporary licenses (see also Installing a Temporary License).