After a sever reboot, the data_engine probe fails to start up with the following error in the data_engine.log:
Sep 30 19:22:03:929 [2052] de: [main] has connected to database
Sep 30 19:22:03:929 [2052] de: Database script - processing 3 database scripts
Sep 30 19:22:03:929 [2052] de: Database script - Module: [ NIS_BASE ], File: [scripts\sqlserver_nis_base_create.sql], run check: [yes], run script: [ no]
Sep 30 19:22:03:945 [2052] de: [main] ExecuteRecords - 1 errors
Sep 30 19:22:03:945 [2052] de: (1) ExecuteRecords [Provider] Class not registered
Sep 30 19:22:03:945 [2052] de: COM Error [0x80040154] Class not registered - [Provider] Class not registered
There were also a handful of other probes that were unable to start (because they rely on data_engine to be running).
This scenario was caused by one or more corrupted .dll files in the C:\Windows\System32 directory.
Check out THIS ARTICLE to see steps for resolution.