C:\testDB folder suddenly created after CCM server restart

We have a distributed v.4.0.4 CLM server env. using windows 2008 server with oracle back-end db.
After a stop and restart of our CCM server last night, the web UI returned the following errors when I logged in this morning.
This application needs to be registered with a Jazz Team Server to function correctly. To proceed, use the Setup Wizard located on the Jazz Team Server (For example: https://servername.domain.com:9443/jts/setup).
Database Status
CRJAZ1061I The database is responding, but the Jazz repository schemas and tables cannot be found. Check that the database JDBC location is correct. If this is a new database, stop the server and use the "repotools" command to create the tables.
I noticed that the DB connection configuration defaulted back to DERBY. The teamserver.properties file was OK - still pointing to the oracle db parameters. Investigation discovered that a new folder called testDb was somehow created automatically under the system root C:\
Resolution:
Stopped the server - deleted the testDB folder - restarted the server. The server is now responding and working as expected. The connection to the oracle db was re-established.
Nothing in the jazz logs or WAS logs can explain how this testDB folder suddenly showed up under the C:\ drive. Also, fyi all our applications are installed on E:\ and not on C:\
This server has been in production for over 2 years and this has never happened before.

Have anybody ever seen this behavior or do you have an explanation as to why this testDB folder would suddenly be created and why the CCM application would default back to use the DERBY database after the restart.

Thanks,
Pierre