"StockItem already exists" error appears when we import the StockItems as shown below :



Here's the video that shows what happens when you import this data into Tally.



WRONG DATA
The aforesaid error appears if the StockItem Names are repeated (as shown below) :


Item NameAliasPartNo
APPLE
A1
BALL
B1
BALL
B2


PS: The StockItem Name cannot be same for two different PartNos.


CORRECT DATA
The same error would appear if the Item Names are repeated (as shown below) :


Item NameAliasPartNo
APPLE (A1)
A1
BALL (B1)
B1
BALL (B2)
B2


PS: The StockItem Name is now unique.