In Windows Vista, you may experience the following symptoms.

Symptom 1
When you try to use Windows Task Scheduler to change the defrag schedule, you may receive the following error message:

Transaction support within the specified file system resource manager is not started or was shut down due to an error.

Symptom 2
When you try to change the settings for a file backup operation, you may receive the following error message:

File backup could not save your automatic backup settings for the following reason:
Transaction support within the specified file system resource manager is not started or was shut down due to an error. (0×80071A91)