Save data after adding new entry

I ran into the same problem and I wasn't satisfied with the answer so I continued Googling and ran into this tutorial:

How to create a trigger that implements the auto save feature

http://www.mydigitallife.info/how-to-auto-save-the-database-in-keepass-password-safe/

1. In KeePass Password Safe, click on Tools menu and select Triggers.
2. Click on Add button to open Add Trigger wizard.
3. Enter a name for the new trigger, such as Auto Save Database, then click Next. Left the “Enabled” and “Initially On” check boxes ticked, and “Turn off after executing actions (run once) check box unticked.
4. On the “Events” tab, click on Add button.
5. Select User interface state updated in the “Event” drop-down list, which evaluates to true when KeePass has finished updating the state of the user interface (menus, toolbar, …), including after most user actions, like adding / editing / deleting entries and groups, etc. Then, click OK, follow by Next in the wizard.
6. Optional: On the “Conditions” tab, click on Add button.
7. Optional (if perform step above):Select Active database has unsaved changes in the “Condition” drop-down list, and click OK, follow by Next in the wizard.
8. On the “Actions” tab, click on Add button.
9. Select Save active database in the “Action” drop-down list, and click OK.
10. Click Finish, follow by OK.

The action to save the password is performed immediately, if there is unsaved changes. After creating the trigger, the Save button will always be disabled or grayed out, as the change is saved instantly on any changes – addition, deletion or edition.

There's an auto-save option in Tools -> Options... -> Advanced. If this sometimes fails to work, it may be a bug. A way to mitigate this is to use a shorter auto-lock period so the database will be saved more frequently.

Also, KeeFox does auto-save when you save a new password from the browser. You may consider using it.

2018 Answer (2.39.1+)

In the newest versions of KeePass you can have autosave on any update of the entry (that includes adding new entries) without any triggers. Just go to Tools -> Options... -> Advanced and click on Automatically save after modifying an entry using the entry editing dialog.

Note: This does not seem to work for deleting of entries.