Oracle Server Troubleshooting and Fixes

When you prepare a Fresh Start machine using DaDesktop (DD), almost all applications work without a hitch. However, a couple of programs can be thrown off by the cloning process and may need a few manual tweaks to get back to normal.

System Details

Oracle Database 19c (other versions will likely behave the same way)
Set up on a Windows 10 template

Fresh Start Fix Notes

Bear in mind that this is a generic guide for resolving issues within a Fresh Start environment. Your exact steps may differ based on your configuration.
In short, the fix works like this: The original hostname of the Fresh Start machine becomes meaningless after cloning, so we replace it with 127.0.0.1 (localhost). Additionally, extra database Listeners often creep in and confuse things, so we remove them as shown below.

Fix process

1. The screenshot below shows a network connection failure when using Oracle SQL Developer.

Failure Test

2. Start the Oracle Net Manager application.

The XE service details appear, including the original host info (in this case alexei-uuae.vm).

Oracle Net Manager

3. The connection test fails (after entering userid=system and the password).

Connection test fails

4. In Oracle Net Manager, go to Listening Locations and then Listener.
The host details show the original hostname 'alexei-uue.vm' — this will be changed.

5. No databases are listed as configured for LISTENER1. Look through all the Listeners for any that have no database services assigned to them. If you find one, delete it.

Listeners

6. So, delete LISTENER1 and confirm. Note: this is just an example of what happened during our setup — it may not apply in every case, but it illustrates the idea.

Delete Listener

7. DEFAULT SERVER LISTENER – examine each Listener one by one. In this example, no listening location is set.

Default Listener

8. Hence, delete the DEFAULT SERVER LISTENER.

Delete Listener

9. On LISTENER (the only one remaining), you can see the old VM hostname that needs updating — it won't match after cloning.

Fix Network

10. Change the host from the current value (for example, 'alexi.uuae.vm') to 127.0.0.1, keeping the port unchanged.

Change Network

Now configure the existing database

11. Set the SID to XE and the Global Database Name to xe.local

Change details of SID and global db name

12. Save the network configuration and close the application.

13. Open a command prompt to restart the listener service.

Type ‘lsnrctl status’, then ‘lsnrctl stop’

Type ‘lsnrctl start’

Cmd prompt

Reopen Oracle Net Manager.

14. From the Service‑naming > xe section, remove 'alexei-vm'.

15. Update the host to 127.0.0.1

16. Save the network connection.

17. Perform a connection test. Click the small button in the image below to start it.

Click to test

18. Adjust the login details: change the username to ‘system’ and enter the password.

Connection test successful

If needed, save the network connection.

19. Return to the main Oracle SQL Developer application and run the connection test again.

Oracle app

20. Assuming the connection is successful, go to the Connections pane on the left, expand Oracle Connections, and verify that the database tables appear as expected.

21. Continue with any further FreshStart machine configuration needed, then clone the FreshStart machines for the trainer and participants.

The Oracle Database server should now work properly on all the trainer and participant machines.

If you still run into problems, please contact DaDesktop Support through the chat app — we're happy to help.