Round corner widget rotates object instead of rounding corner

Go to Object > Expand appearance. Should work fine after that.

I DONT have a fix, but I DO have a very simple workaround that has worked for me:

Select your object using selection tool (V), then change to direction selection tool (A) to select the corner widget.

(This will adjust all corners.)

For whatever reason, I am always able to grab the corner widget just fine when I change the selection tool, and never when I use the direct selection no matter the zoom or mouse position. Now that I've figured it out, it is just the minor inconvenience of using the shortcut keys when I have to adjust corners. Let me know if this works for anyone else...

Wow! Talk about disappointing. I'm completely new to Illustrator and I'm following the Getting Started In Illustrator Course. I am only on the second lesson, Create and Edit Shapes and I've already run into this problem and found my way to this forum post.

Here's what I have discovered with 10 minutes of searching and playing around.

1. Zoom in to your artboard to 400% magnification and create a rectangle. The corner widgets will only rotate the shape.

2. Zoom out to 100% magnification and now the corner widgets work correctly.

3. Once you have moved the corner widgets and rounded the corners they will continue to work correctly if you return to a greater level of magnification.

I'm 20 minutes into learning the software and already I am bug fixing! Does nobody write good software anymore?

 In the meantime, try View>Hide  Corner Widget

Use Direct Tool to select the anchor points and change rounded corners using the Properties Panel.

Happening to me too.

Shocking that Adobe can have this error on the most simple action, and not fix it in two and a half years

This has been happening to me for more than half a year now (I recall first noticing this behaviour around Feburary or March). It's now November and several updates later, and it's still sticking around. Same behaviour as what the original post describes - hovering over the Live Corner widgets shows the cursor change, but then when I click and drag it the whole object rotates as well. Has the Illustrator team been able to replicate or experience the same problem? It's frustrating and slows down my workflow a lot.

Same for me. I'm using a triangle shape so the widget is extremely close to the edges, but I hover over the widget, see the curve shows under the selection tool, and then when I click, it starts rotating the triangle. I would love to see this bug fixed.

With your experience, I'm sure you're aware the rotate function should become available when the pointer is outside the bounding box, whereas the corner widget is typically seen on the interior (acute side of a given path-angle apex). So it seems you're truly seeing a malfunction; the kind of malfunction that can often be cleared up with a reset of preferences. Have you tried that?