After IPL and restart , Datacom Multi-User startup gives this open error :
DB00501E - OPEN ERROR - RETURN CODE 43 (007) CXX=name (ADS01007) ***DBOPN S
z/OS
Datacom/AD 15.1
DB00501E - OPEN ERROR - RETURN CODE 43 (007) CXX=name (ADS01007) means that the index for DBID 1007 has not been built.
Note that DBID 1007 is an optional system data base . The MUF tries to open the base because the MUF startup card HISTORY 1007 is present.
You can recreate the base by copying members AX15HST1 and AX15HST2 from the AD 15.1 CAAXSAMP to your INSTJCL data set and run them.
Those optional jobs are documented here in Optional Jobs