I forgot to make a copy of this AutoCAD file before I started to change it. OOPS! It happens. So what can you do? First of all, if you are making a major change to an existing AutoCAD file it is a good idea to make a copy (an historical archive) of the file before you change it. That way you have an electronic copy of what you submitted that you can go back to. There are many reasons why you may need to revisit an old design or an older version of a drawing. Minor changes may not require an archive, but what constitutes a minor change?
This has happened to me several times. I started working on a file before I made an archival copy. If you haven’t saved the file then no harm done. Quickly make a copy before you save the file. If you have saved it, but only once, then check the .BAK version of the files. It should be located in the same folder as the .DWG file. Rename the file and change the extension from .BAK to .DWG. If it’s your old file then you are in luck.
AutoCAD automatically generates a .BAK version of your file every time you save your file. If you have only saved the file one time then the .BAK file is the original version of the file. If you saved the file two times or more, then your original version is lost. So what do you do? Here’s a trick that I have done several times.
Save your file as is. That will save the work you have already done. Don’t close the file. Now “saveas” the file. Save it with a different name (save it according to your company’s archival renaming methods, whatever they may be). We have saved the work you already did and now we changed which file you were working in through the “saveas”. Now undo everything. Yes, everything. None of your work is lost because we performed a save. Then we switched files by performing a saveas. Once everything is undone, save.
Now you have an archive of the file before you made changes to it.