One nice addition to Puppy beginning somewhere around version 2.17 is the ability to mount a .2fs or .sfs file simply by left clicking on it. If you have more than one installation of Puppy on your computer, you may want to mount a pup_save.2fs save file from one of the other installations to copy or otherwise make use of data stored there. However, if the .2fs file has the same name as the file used on your active installation, you get a message that says something like "Sorry /mnt/hda4/p301/pup_save.2fs is already mounted and in-use by Puppy".
There is an easy fix. Just right click on it and temporarily rename the file to something else like "pup_save1.2fs". Then you can mount it with no trouble. Just remember to unmount the file after you are done with it by left clicking it again and to rename it back to its original name. Next time you run the installation that it is part of, it will work as if nothing happened.
