You may encounter PowerPivot data refresh schedules getting automatically disabled in SharePoint 2013. If a schedule gets disabled, you may see one of the following messages when viewing the Data Refresh History page:
The schedule was disabled due to consecutive failures.
The schedule was disabled because the workbook is inactive.
There a couple settings in the PowerPivot service application settings that can cause schedules to be come disabled due to the reasons stated in the messages above. Here is a screenshot of those settings that you can access in SharePoint Central Administration > PowerPivot Management Dashboard > Configure service application settings:
The first settings is Disable data refresh due to consecutive failures and the default value is 10. This means that if a data refresh schedule encounters 10 consecutive failures, the schedule will be disabled. The second setting is Disable data refresh for inactive workbooks and the default value is also 10. This means if a workbook has not been accessed by a user for 10 days, the schedule will be disabled.
You can specify a different value for these settings. To prevent the data refresh schedule from becoming disabled automatically due to failures or inactivity, specify a value of 0 for these settings.