VBA taking more and more time

[Pierre]

Hello,

I made a macro to automatize a calculation process for our warehouse. The code and calculation are correct but I noticed that over time it's taking more and more time. My colleague using the file came back to me and told me that the calculation is now taking hours.
He sent me the file he used, I tested and saw it was very slow. What I did is copy data and macro in a new file and then run the macro, it took only 2min.

Has someone ever noticed this?

I join the 2 files, is there something inside that can explain the difference in speed? Is there a way to avoid this?

 

[Chihiro]

First, both files have unnecessary format beyond last data range. You can check this by using CTRL + END.

As well, Long_Calculation has another hidden sheet, which has formula dependent on column AE. This will add another layer of slow down, as each loop seems to cause this to recalculate.