Message：
Unable to start execution of step 3 (reason: The PowerShell subsystem failed to load [see the SQLAGENT.OUT file for details]; The job has been suspended). The step failed.
Action:
The error indicates the invalid location of SQLPS.exe file. To troubleshoot the issue, please follow the below steps:
1. Execute the following statements to check the location of SQLPS.exe file.
SELECT * FROM msdb.dbo.syssubsystems WHERE start_entry_point =‘PowerShellStart‘
2.update the correct sqlps.exe location path.
Update msdb.dbo.syssubsystems set agent_exe=‘D:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\SQLPS.exe‘
WHERE start_entry_point =‘PowerShellStart‘
3.restart sql agent services and then rerun the job.
SQL Server-sys purge history job failed issue
原文：http://www.cnblogs.com/roseHLF/p/7009853.html