Append Range Error

I want to merge excel file A to B. Both files have the same columns.

My flow:
1 read range
2 append range
3. write CSV

It works when B just contains headers.

But if B contains data rows, it not work.
Error message : Append Range: Row number must be between 1 and 1048576

Hi
welcome to uipath community
Append range is used to append a datatable directly to a excel
are we trying to do that
OR
we want that datatable to be merged with someother datatable
in that case we can use MERGE DATATABLE activity and then use WRITE CSV

Cheers @Fey

Hi @Palaniyappan. Thanks for your reply!

Yes, I want to append a datatable directly to an excel file. I did extra work. It‘s no need to write csv.:joy:

I have tried two situations as below:
Situation 1 (Work)
File A
name id
a 1
b 2
File B
name id
After run:
File B
name id
a 1
b 2

Situation 2 (not work)
File A
name id
a 1
b 2
File B
name id
c 3
d 4
After run:
Error: Row number must be between 1 and 1048576

How to make the situation 2 work? I want the result like:
File B
name id
c 3
d 4
a 1
b 2