When you upload a new sketch, what happens to the old sketch? Does it get overwritten?
Yep. Gone for good.
If you want to disable the autosave feature, you can go to file>preferences, then uncheck the box that says "save when verifying or uploading"
Bluenick2100:
If you want to disable the autosave feature, you can go to file>preferences, then uncheck the box that says "save when verifying or uploading"
That affects the saving of sketches on your computer, but it makes no difference to how the previous sketch on the Arduino board is overwritten when you upload a new one.
see your first reply