Troubleshooting - Disappering configuration.mof File

Symptoms:

   Recently we noticed an unexpected behavior of Hardware Inventory settings applied in the configuration.mof file on one of our SCCM instances. None of the WMI classes introduced into the file were collected and upon re-checking the file it turned out, that any newly added section were being removed and the file was reverted to it's original form. Interestingly enough, the section added did not contain any errors, as this was happening even in case of adding additional spaces or new lines to the file - they would disappear as well.

Resolution:

    My first suspicion was to verify the extension added by the custom HP inventory module solution, which was only applied on this particular instance and added the following section at the end of the configuration.mof file:

Extension added to configuration.mof file by a custom HP plugin

    Removing this section however didn't take an effect either - the file was restored and the section re-appeared. An action was reflected in the dataldr.log file with the following entries:

MofCompiler failed:
parsing error
Failed to confert MOF class/poperties to policy; a retry will be attemted in 30 seconds...

Errors in the dataldr.log file

    Despite no apparent syntax problems the file refused to get parsed. Even voiding each section one by one didn't fix the problem - an empty file would get removed and restored from backup too. What helped to pinpoint the problem was running file comparison tool FC.exe - against another configuration.mof file from the properly working environment. This revealed the following phenomenon:

Errors in the dataldr.log file

    Apparently the beginning of the file was taken by some special character invisible either notepad or any other editing tool that was available. The problem was fixed by replacing the file with a properly working one and transplanting custom sections from the old faulty one. Looking at the history of the changes it seems that the latest accepted change to the file was accepted after adding the custom HP SCCM plugin