I have VBA code in file A, there are many files in a folder, I copy many data from each file in the folder to file B.

Files A and B are not in the folder. If I run many files in folder, the program could fail. If I break those files into a few folders, then it run fine on each folder. That means the files are fine within the folder.

Maybe it is excel memory issue? Too much information on clipboard?

Thanks.