What are possible causes of the error message “Data files are corrupted or missing”?

The error message "Data files are corrupted or missing." has been seen from MassHunter Acq B.06.XX

It has been found that there was an issue with Optimizer B.06.00.

It commonly occurs when the DefaultDatabase field in the D:\MassHunter\Configuration\Optimizer\OptCompoundBrowserConfig.xml file has an invalid value. Most likely, because a database that has been renamed or moved.

With B.06.00 and earlier when the Optimizer cannot find the database as specified in this value, it displayed the error "Datafile are corrupted or missing" and quits.

With B.07.00 and beyond, when Optimizer cannot find the database it defaults to D:\MassHunter\Databases\Optimizer - which should always be present.

The workaround documented for B06.XX:

"When this occurs, you can get Optimizer to run again if you make sure the Optimizer can access the database that is specified in the OptCompoundBrowserConfig.xml file.

Open the file /Configuration/Optimizer/OptCompoundBrowserConfig.xml.

Inspect the entry.Make sure the directory specified there exists.

The default value is D:\MassHunter\Databases\Optimizer"

Further, for all cases where this problem was seen, the PC needed to be re-imaged, or a clean reinstallation performed (removing all MassHunter software and the all entries from the registry was needed).