I know I must have toggled something but for the life of me I can't figure it out. In this one Blender file any time I make a curve and go into Edit mode I cannot adjust the handles of the curve. The handles are there but whatever point I click on(be it vertex or handle) and try to move it, the whole curve moves. However if I open up a different or new project the curve handles work just fine and I can change the shape of the curve with ease. I can't seem to find the solution anywhere. If someone could help be I would truly appreciate it.
Do you have proportional editing turned on? Toggle this on/off to see if your proportional editing zone is simply not visible and gives the impression the entire curve is moving as you try to adjust.