A pair of tags I came across on Super User - both task-scheduler and windows-task-scheduler exist, but as far I can see they're both the same thing:
task-scheduler: a component in Windows that, like the unix cron daemon, allows scripts to be run at defined times. (questions)
windows-task-scheduler: a component of Microsoft Windows that provides the ability to schedule the launch of programs or scripts at predefined times (questions)
Some of the questions are tagged with both.
Edit: This is a clearcut synonym request that was raised over 5 years ago but has not been acted on. It was bumped 2 years ago by incorporating it into another tag cleanup effort and making it a duplicate of that. However, it didn't get handled then, either. The task-scheduler tag has recently been cleaned up in preparation for making it a synonym. Please reopen this question and synonomize the tags.