Sometimes a poorly framed query or collection can cause SCCM collections to be left forever in an evaluation state. As a result, the TempDB for the SCCM server can grow to the point where it fills the available drive space. When that happens, SQL stops, and SCCM stops.
Some advice: TempDB is recreated when the SQL Server service is restarted. This is your first action to clear the problem. You should thereafter restart the SMS Executive service.
As the tempdb begins to grow, you can find out what is going on by looking at reports. In the SQL Server Management Studio, expand system databases, right clicking on tempdb, and selecting Reports/Standard Reports. “Top Transactions By Age” will show you what has been stuck, and can give you evidence to track back from there.
In a large SCCM environment, keeping track of the tempdb can be time consuming. SCCM TempDB Space.vbs will connect to the SCCM database and report tempdb size, path, and free space from all site servers. The script has some interesting combinations of WMI queries and SQL queries.