Donation edition will not activate

[stefanz]

Had to replace a main board on machine, and the FFS came up with an error.

I went ahead and donated again and downloaded a new later version. Installed over the top, then uninstalled and reinstalled new again. Still error. See attached.

[Plerry]

The message FFS shows you is pretty clear.
The donation edition is already registered on 12 devices/installations.
(Note that each virtual machine on which FFS is installed counts as a separate device.)
From the FFS FAQs: "The FreeFileSync Donation Edition is expected to be used by you and your friends."
More than 12 installations is considered to be beyond said expectation.

By replacing your motherboard, one or more of your 12 registered FFS installations are no longer in use.
If you go to the FFS donation edition download page (e.g. via the link you received in the E-mail after donating) you should see "FreeFileSync is installed on X devices", where in your case X is probably 12.
If you click the the Show button behind above text, the page lists all your devices on which an FFS installation is registered.
If you hoover your mouse over a registered installation, you get the option to remove that installation from the list, thus freeing up registrations for use on another device.
Note that it can take up to 48 hours for the removal to take effect.

[Zenju]

Two corrections:
1. deletion is instant, but isn't allowed for newly installed devices
2. Virtual Machines do not add to the device count