I can no longer record 3 non-HD shows at the same time; previously I was able to do so.

Same here.

Let's make sure you can record all your shows at once, @cadylake! 

We recommend using the Troubleshoot & Resolve Tool on your TV. You should have access at least 3 SD recordings, so this is likely caused by a technical issue. 

1. Press Menu on the U-verse Remote Control.   
2. Scroll down to Help, then press OK.   
3. Select Information.
4. Scroll to Troubleshoot & Resolve, then press OK.   
5. Select the service you want to troubleshoot and allow the interactive diagnostic test to run and complete.   
6. Follow the onscreen instructions to resolve. Other options may include dispatching a technician or speaking to a Customer Care agent.

If this doesn't help, please let us know. We may need to replace your DVR.

Raiden, AT&T Community Specialist