New Program Guide Look

No way to convert back. What device are you using?

I haven't noticed any changes. What streaming device are you using?

Can you post a pic so we know what you are talking about?

The guide hasn't changed for me in like 6 months. Do you mean the home screen?

The biggest change is in the DirecTV Stream devices. I think it is a great improvement. It opens up to a single screen that you can see the menu on the left side of the screen. You also see the last 8 channels you have watched, and a screen that shows a live screen of the one you select.  
The Fire Stick and Roku app screens Show the What's on now, of the last few channels you have viewed. And the menu on the left side of the screen. Just doesn't have the Live screen like the DirecTV Screen box has. 
DirecTV Stream box screen:

The Roku or Fire Stick screen:

If the OP does not like the new Home Screen they can turn it off in settings under preferences.  I would assume that is what they are talking about but waiting for them to respond to the comments.

For a few weeks the guide was in larger font and easier to read.   When the new “Home Screen” came out, the guide font was returned to what it was before-smaller.   

Why does my picture open up with a black live screen. See attachment. I have TCL ROKU TV

No idea. Looks like it just did not load. Everything else did.

I hate it. I can't figure out how to get to the menu. Can't delete recordings I don't want.

All the menu's are on the left side of the screen including "my library"