Looping through workbooks and copy pasting data between dates

Hello,

The big challenge for large workbooks is to cope with the core structure which was picked at the very beginning ...

Indeed, the various consequences of a bad structure do lead to many obstacles, such as difficulties and obstacles to handle data.

Quite often, processing data does become very slow, and the crucial step of Analysis tends to be very cumbersome.

To be effective, designing Excel spreadsheets should stick to following 7 Golden Rules:   7 Golden Rules for Spreadsheet Design

Another link extremely well built by Dave to help designing Excel spreadsheets : Dave's unvaluable recommendations

As a consequence of improper design, users tend to continue adding "patches" ... to avoid investing the time and effort to rebuild everything from scratch.

When it comes to several large workbooks, one should consider working with flat files to replicate databases, and operate much more efficiently and rapidly with closed files, using, for example, techniques such as ADO. see link below:

Import data from a closed workbook (ADO) using VBA in Microsoft Excel

Hope this will help

You are welcome

Very sorry for the bad news ...

Hi again,

Among the "patches" to improve the speed of your macros, there is the following usual recommendation :

 ' At the very beginning of your macro
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
'
' Your Macro as it is currently ...
'
' At the very end of your macro
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True

Hope this will bring some improvement