SQL Server Maintenance Plan Cleanup not working

Like many folk, I've recently been caught out by the bug in SQL Server 2008 Maintenance Plan Cleanup tasks apparently running OK but not actually deleting files and the backup volume filling up.

This is caused by the trailing slash '\' being omitted from the folder path and giving the file extension as .BAK (or .TRN) and not just BAK (or TRN) without the . (dot) when editing the subplan properties. Correct this and everything works OK. James Howard provides a slightly longer explanation in his blog on this issue.