Sync shares all selected data between all systems/profiles that are logged in. There is no 'master.'

Explain what it is you want to do.

I want the sync process to proceed in one direction only -- from desktop as source to mobile as target. More specificially, I want to transfer the bookmarks from my desktop Firefox to my mobile Firefox. I do not want any changes made to my desktop Firefox (when I activated Autosync from the mobile phone, for example, the bookmarks on my desktop Firefox were deleted, and I don't want this result). From the Mozilla literature that I have read, and also from your response, it appears that what I want to do cannot be done, at least not currently.

Bookmarks shouldn't get deleted by Sync, but when doing an initial Sync to a "new" device bookmarks do get "scrambled" sometimes as they get merged to an existing device from the "new" device. Over the course of time (hours or days) depending upon how many bookmarks are involved or how often Firefox is opened & closed that "scrambling" should get straightened out. somewhat. Seems to be worse when a "mobile" device is involved as not all "desktop" bookmarks get sent to the "mobile" device, or so I have read.

As Fred mentioned, there is no one-way control not is there a "push" or "pull" setting or control; the data is shared almost equally with "mobile" not always getting all "desktop" bookmarks nor is browsing history equal between any type device, but as with bookmarks "mobile" gets less history than another "desktop" device would receive.

And "Sync now" is really only for sending Tabs data to the Sync server so you can do an immediate send when two devices have Firefox running at the same time.

Thank you for the explanation. It seems to me that Mozilla probably knows about the inconsistency of the sync results, as you described, and will hopefully improve the sync feature at some point.

I have enough information to cope with the situation now, so I have requested that this query be closed.