SharePoint 2013 Workflows disappeared from SP Designer and Multiple Site Collections
Workflows were gone from SP Designer and all sites. 2010 workflows were still present but deprecated as expected. Issue appeared to have started around 11/15 but was not discovered until 12/2, all workflows had not been running during that time and appeared to be deleted off of all sites. Workflows were not in recycle bin. Workflows suddenly reappeared in Designer and sites 12/3 after issue was reported to Microsoft Support.