Hi, do you mean Shortcuts on the new tab page in Firefox, or shortcuts on your Windows desktop?

New tab page pinned sites do Sync, but I don't know what would cause that to fail or work backwards. You can turn off Sync for that list so each Firefox installation can have a separate list, but we would still need to consider how you might recover the old list (a bit complicated, but if you have a backup, there probably is a way to do it).

If you use Avast/AVG:

A false positive detection earlier this week caused the prefs.js file to get quarantined. This file stores your home page URL, many custom settings, AND your new tab page pinned Shortcut details. You could check the quarantine and consider making an exception for the file to restore the earlier version. I'm not sure how that will affect your Sync setup, however.

Hello. Sorry, The missing items are Shortcuts on the new tab page in Firefox. Here's the scenario: - 1st PC is Windows 10 Pro and used to sync other PCs - 2nd/3rd laptops with various flavors of Linux configured as multi-boot OS systems with each OS using Firefox as main browser

I 1st used Firefox Sync to upload Windows 10 configs. I then signed in from a Linux (PopOS) Firefox and sync appeared to work. Logging into another Linux instance (Manjaro) and attempting to sync uploaded the Manjaro Shortcuts overwriting the original tab page Shortcuts and subsequently syncing other logged in PCs to the Manjaro new tab page completely eliminating the original new tab page.  

Maybe I'm misunderstanding how Sync is meant to be used, but this is concerning. I currently have ONLY one instance of Firefox logged into Sync at a time in hopes of not having this happen again. Any insight would be appreciated.

Regards