checking for duplicates when creating macro to move data into master sheet

[aleisaab]

Hello Everyone. I am a new student to VBA and am amazed by the unlimited capabilities of it. I honestly need ur help in my first macro. I created a macro that extracts monthly sales from a text file, formats it, and then sends it to the master sheet with sales for previous months. the Function adds new data at the bottom of the master sheet. I created a button that will trigger this entire action, but what if i accidentally click the button twice and the information is duplicated? your support is sincerely appreciated.

 

[Crystalyzer]

Can you post the code and the worksheet using XL2BB?