MEM CTLR DESCRIBED DATA BLOCK ANOMALY THAT CAUSED UNNECESSARY DISTRACTION.

Narrative

I WAS WORKING W DEP WHEN ACR X AN E170; DEPARTED MEM ON A 180 DEG HDG LOOKING TO GO WBOUND. THE DATA BLOCK DID NOT APPEAR FOR ACR X; SO I ATTEMPTED TO MANUALLY START THE DATA BLOCK. MY ATTEMPT FAILED AND I AND THE COORDINATOR COULD NOT FIGURE OUT WHY. AT THE TIME; I HAD XING ACFT CLBING AND DSNDING THROUGH EACH OTHERS' ALTS; AN ACFT DEVIATING FOR WX THAT DID NOT APPEAR ON MY SCOPE; AND ANOTHER ACFT THAT WAS WILLING TO FLY THROUGH THE NON-DEPICTED WX; THAT NEEDED TO BE IN TRAIL OF THE DEVIATING ACFT. DURING MY SCAN; I SAW AN ARR ACFT WHOSE CALL SIGN WAS ACR X. I REALIZED AT THIS POINT THAT THE ARR ACFT WAS THE REASON FOR MY INABILITY TO MANUALLY TAG MY DEP. THE COORDINATOR MADE SEVERAL COMPUTER ENTRIES AND MY DEP TAGGED UP. WHEN THIS DUPLICATE IDENT FOR INBOUNDS AND OUTBOUNDS IS A POSSIBILITY FOR ACR X AND ACR Y THEY AMEND THE DEPS CALL SIGNS BY ADDING A LETTER OR SUBTRACTING A DIGIT AND ADDING A NUMBER SO THAT THE CALL SIGNS ARE DIFFERENT. NEEDLESS TO SAY; THIS WAS AN UNNECESSARY DISTR THAT TOOK MY ATTN FROM THE SEPARATION OF ACFT.