Small Thing Makes Horrid Mess

These are stories where some small change, small typo, or small movement causes large messes. It is about the large "size difference" between the change or item compared to the result. Perhaps it could be called "leveraged chaos".

I had an auto-run DOS batch file which periodically copies over files from one server to another using the "new files only" flag. Basically it is folder replication. It was a recursive copy (flag /S), such that all subfolders were also to be copied.

I mapped a drive letter, X: for example, to the source folder. However, X: somehow got remapped to the root of the source server. This resulted in boatloads of files being moved over, the entire server contents, making a giant mess. To prevent this in the future, I now reference the source via an added path. Example: "X:/source_folder/*.*". I basically mapped X: to one level lower. This way if X: somehow gets remapped again, it won't work unless the new (wrong) path happens to have a folder named "source_folder", which is both unlikely and limits the probable size of the error even if it had such a folder.