Have to open Macbook lid after sleep to display on Thunderbolt

[Pjrufus]

This is a new issue, started about a week ago and it's making me crazy. Macbook Pro connected to a Thunderbolt Display. Nothing has been updated since this started. Before, when in sleep mode, I just clicked on the mouse button (trackball) and the desktop would be on the display. Now, after sleep, the display lights but is blank, and I have to open and close the MB lid for the desktop to appear.

If anyone has any ideas on this I would be grateful.

 

[Weaselboy]

Try an SMC reset.

 

[Pjrufus]

Thank you. Had no idea what that was, looked it up. I'll report back after trying it.

 

[Pjrufus]

Sorry to take so long to report back. Finally had time to look into this. Decided to try updating everything that needed updating and restarting, before trying the SMC reset. It was a few days ago, and everything's been fine since. Didn't have to reset SMC. Thank you again for the help.