Turns out there was a second job setup calling the same maintenance plan.  Once I disabled that second job it started working.

Hi Sue,
Thanks for the response.
Expanding the history event in the job history reveals this:
Microsoft (R) SQL Server Execute Package Utility  Version 10.50.2500.0 for 64-bit ...

Results from that command....

"No items found that satisfy the query."

The task in the maintenance plan has the backup compression set to server default. The server properties show the compress backup setting as unchecked.

I've done the backup routine steps one at a time. There is plenty of space left even before the old backups are removed.

Can you be more specific? What temp space are you referring to? tempdb? The OS temp directory?

This post specified that SQL doesn't use temp space for backup:

Backing up to a local drive on the server