Hi Jim, thank you for your help. I changed the code with rlock() and it seems to work now. I think your code is much tidier. I found that if I don't close the files, the number does not change sometimes ???

IF USED("barcno")
	USE IN barcno
ENDIF
IF NOT USED("barcno")
	SELECT 0
	USE barcno
endif		
select barcno 

nBarc=barcno.barcno  
IF nBarc <= 0
	MESSAGEBOX("This computer is not setup with barcode numbers","")
	RETURN
ENDIF 
IF RLOCK('barcno')	
	replace barcno with nBarc+1
	UNLOCK
else 
       MESSAGEBOX("The barcodes numbering file is in use, plese try again","")
	RETURN
ENDIF 	
FLUSH in barcno force
IF USED("barcno")
	USE IN barcno
ENDIF