Hi, I've just started with my UNO and the IDE application interface but fell into a big hole:
I'm used to MS Windows and intuitively how I expect applications to work. I loaded and ran a demo then modified the code, tested and uploaded it to UNO. Then I made some bad typo errors with cut and paste and thought I'd revert back as I'd not done a save.
First I tried just closing the application window, started it up and there was the corrupt code I had just left! I had previously tried 'Save As' but it didn't do what I expected. The net result seemed to be that despite not wanting the app to save my corrupt code, it did so (whether in the background, caching or not?) and I couldn't recover the previous working version. Most Windows drawing apps I use (like Eagle) maintain a save list each time the current file is altered or it's a selectable auto save option.
If somebody can understand my story, can they please explain the concepts behind the Arduino application for building and saving sketches? Until I understand what's going on I'm copying and pasting the edit screen into Notepad for backup and using the Archive sketch feature.