If you've got multiple subfolders, the file will simply be copied into (in the new location) one of the other subfolders, unless you've specified that it's going to be replaced with a subfolder whose name is the same as the parent folder's name.” The above is useful if you have folders with names that vary due to changes in the original folders. Also, Merging files will inherit any changes made to the contents of the files inside the other folder. It is a perfect way of copying the contents of several folders/subfolders into a subfolder with the same name from a different file. Aug 20, 2023 — The default behavior of the Finder doesn't account for a new “Merge all files and folders,” available when the merge process goes through the “Check for changes” option in the Finder's window. When merging, this feature can be activated by holding down the Option key while dragging a folder or files to merge or replace. It will then check each folder and file to determine if all are different, and then move them together if the files match in all cases. You can check the contents of your Mac's Trash if you would like to preserve anything not changed by this process (as it'll be there waiting to be overwritten by the new file anyway) by using the Restore button. When all files and folders have been selected, the file will be copied to a destination directory. If you want to copy one or more files over an existing destination directory, drag the files to another location on the Finder's window, or click the “Merge” button to begin the process. When you're done merging or replacing, the Finder will list any changes you've made to the target destination. Press the “Merge all files” option and go through these changes. You will have to manually delete files and folders that were merged. To see if this worked, do a “check” in the contents of the directory on the Source machine and a “search” in the Destination as well. You can then drag those folders to the Source, and they will be deleted, in case the folder didn't change in any other way. If the merge of folders fails, the process will be repeated until you reach the same destination directory. As an example, suppose that you have folders A and B with subfolders D. You want to get rid of directory D and try again.