How you can really sync it to all of your devices is by turn on the Sync for each of your devices and you should then receive all the data that the Firefox Sync server has.

This is because the server usually will try to Sync all of the selected things that you want it to be sync which include your "history" between all of your 3 devices. Sync itself is not intended to be used as a backup server but is just use as a temporary repository until the data may be Synced to each of other devices.

You may refer to this How do I choose what information to sync on Firefox?

Steps:

1. Option out of Syncing History in 1 one of your prefer devices. 2. Manually delete all of the history that you do not wish or do not want to Sync by using the same 1 prefer devices. **Just make sure you really check it thoroughly and delete those history that you do not want it to be in your history list in all of your 3 other devices. 3. Once you has confirm that the unwanted history has been deleted and not exist anymore in your history list in 1 of your prefer devices, now the next step is by using the prefer devices that you has performed all the step above, you need to "Re-enable the Syncing of History".

By doing so, all of your other sync devices should be deleting all of the unwanted history based on what you have done using the prefer devices earlier.

Hi Nadhra,

Thanks for your thorough reply. I'm marking this as solved, but I should have been clearer. I'm looking for a "one-click" solution. Clearly, Firefox doesn't yet have one. I delete history multiple times per day, and the current method is far too time-consuming with multiple devices. I'll see if I can add this as a feature request.

Thanks again!