When you open up a SAS macro catalog so that its entries for use by other programs, it has a major impact on the ability to change the library reference used to access the catalog after it has apparently been unlocked.
options mstored sasmstore=bld_v001;
Using the line above will open the catalog for reading but there is no way to close it in order to change the library reference or deassign it until the SAS session is shut down. Even this line will not do the trick:
options nomstored sasmstore=”;
What it means in practice is that if you have a standard macro setting up access to a number of standard macro libraries, then that setup macro needs to check for any library references used and not try to reassign them, causing errors in the process.