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  de: [main] has connected to database
Sep 30 19:22:03:929  de: Database script - processing 3 database scripts
Sep 30 19:22:03:929  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  de: [main] ExecuteRecords - 1 errors
Sep 30 19:22:03:945  de: (1) ExecuteRecords [Provider] Class not registered
Sep 30 19:22:03:945  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 issue was found using UIM 8.4 and Windows 2008 R2, but the information is generally applicable to most versions of UIM.
This scenario was caused by one or more corrupted .dll files in the C:\Windows\System32 directory.
1. Disable the UIM service on the primary hub
2. Run this command to search for issues on the file system (search only)
3. Should that return an integrity violation, run the following to correct it:
4. After completion ("Windows Resource Protection found corrupt files and successfully repaired them." ), start the UIM service back up on the primary hub
The data_engine probe should then be able to start up and connect with the database.
System File Check (SFC) - https://msdn.microsoft.com/en-us/library/windows/desktop/aa382541(v=vs.85).aspx
Using SFC - https://support.microsoft.com/en-us/kb/929833