works great... Rated 3 out of 5 stars

But when it screws up, it can screw up big time. Thankfully you have snapshots that go far back.
Need support for mobile Firefox now.

unknown synchronization error!!! Rated 2 out of 5 stars

Since I had updated Firefox to v50.0, x-marks add-on was automatically disabled in my add-ons list (it was disabled as unsigned). Last week I upgraded Firefox to v50.1 and yesterday I re-installed the add-on and although the add-on version is still the same v4.3.19, it now loads normally.

However, it cannot synchronize as it used to and it does not create a new backup. After pressing the button to synchronize manually the following message appears:
"An unknown synchronization error has occurred"
and of course my last sync remains the one I had since 27-Nov-2016.

I only try to sync my bookmarks which should be the easiest to avoid any errors in synchronization process.

I use Firefox v50.1 and X-marks v4.3.19.

Please advise what to do to make it work.
Thank you.

This user has a previous review of this add-on.

X-Marks 4.3.19 Keeps Hanging FIrefox 50.1 Rated 2 out of 5 stars

I have used X-Marks for years, since long before it was bought by LastPass. When it works, it's an excellent program for syncing bookmarks and other data across browsers. I have, however, experienced repeated (and essentially unavoidable) hangs/crashes when using the latest iteration of X-Marks (v. 4.3.19) with the latest version of Firefox (v. 50.1). Just be aware of this...

This addon is a joke Rated 1 out of 5 stars

This addon used to be good years ago...

Now it simply awful.

After numerous issues, I tried to sync between firefox and safari :

I deleted the bookmarks i didn't want anymore on firefox, forced my firefox bookmarks to override server data, and overrided the bookmarks on safari with the server data...

Three days later, the bookmarks i deleted on firefox were back, completely messed and mixed.

It just became a complete shitware...

Still good Rated 3 out of 5 stars

I've used it for a long time. It could be better, but there's not a lot of competition and it has more usefulness (for me) than the alternatives. The developers continue with periodic updates and fixes, so I have hope. Plus, I don't want to bother to learn another system.

History info and bookmark info - not there Rated 1 out of 5 stars

I read that this add-on would show me if I have visited a site when I go there. I also thought it would tell me if that site is bookmarked. It does neither. I guess LASTPAST removed those options.

So, what good is it? And, from what I've read in other reviews, the last thing I want to use Xmarks for is to Sync. Such horrors stories. I dislike Firefox Sync, because I have no control. But, at least it doesn't mess up my bookmarks.

Was good - now horrible Rated 1 out of 5 stars

Was a fan before but obviously LastPass sacked everyone and just left the structure in place with little or no support.
Not fit for purpose now.

Avoid Rated 2 out of 5 stars

Screwed up my bookmarks at least once a month until I came to my senses and uninstalled it.

I recommend it Rated 5 out of 5 stars

I use it since for a long time and it is a success.

e10s support? bugfixes? Rated 2 out of 5 stars

This addon is one of the few solutions for cross-browser bookmarks, but unfortunately lack of maintenance shows:
* as said elsewhere, it may un-nest your folders on first sync and even create empty duplicated folders
* When switching browsers frequently, it often bails out, asking you to override local bookmarks with a fresh copy from the server.
* such downloads sometimes end up reordering all your bookmarks (easy to fix with "sort by name"... only if that's how you had them sorted before)
* no "restartless" and "e10s" compatibility, even though at least e10s would be easy to add as the addon presumably doesn't need access to the page content to sync bookmarks

Xmarks - DUPLICATE NAME BOOKMARK FOLDERS WOULD BE LOST !!!! Rated 1 out of 5 stars

I used it on the Chrome and Firefox. Than Sync errors started so had to stop using it on Chrome. A few days ago realized I lost duplicate name Bookmark Folders. Shame I have stopped using it and users please note: DUPLICATE BOOKMARK FOLDERS WOULD BE LOST !!!!
There is way to recover it, already done once, please go and follow their recovery info if you need it

#1 MOST AWFUL PLUGIN I HAVE EVER SEEN, IT WILL TOTALLY SCREW UP ALL YOUR BOOKMARKS Rated 1 out of 5 stars

This horrible plugin will scramble up all your bookmarks, de-nest and fragment all the sub-categories of bookmarks you had created (except for some which only get partially messed up, but those get rearranged so they're useless!), make duplicates of your bookmarks in random inappropriate places, and you'll never be able to find anything using your bookmarks again. The people who 'like' this horrid piece of crapware must have maybe one or two dozen bookmarks to deal with which they don't mind fixing all the time, but I had saved hundreds and now they're all a useless scrambled mess. So now I have to find some kind of utility that will allow me to re-organize them all, or else just delete them all and start over. I wish I could rate this piece of crap in negative stars or at least a ZERO.

IT ALSO MAKES FIREFOX HANG ALL THE TIME SO THAT YOU HAVE TO EXIT AND RESTART! Whoever is pimping this garbageware is doing a great disservice to people.

NOTE: when you go to expunge this awful software from your system you have to DELETE it from the appropriate Add-Ons areas of both Chrome and Firefox (I wouldn't recommend just deactivating, this horrid software is insidious), but then you ALSO have to go in and delete it in Control Panel => Programs and Features because that is apparently where it is set up to corrupt all your bookmarks in MSIE. If you don't do this you'll keep getting a popup message with a couple of cryptic choices that don't make much sense beyond they want to screw up your system even more, forcing you to Cancel out until you've finally deleted Xmarks there too. However, one machine I cleaned up did not show Xmarks in that area and I never figured out why, but just removing it from Firefox and Chrome was sufficient. All my machines running Xmarks used Windows 10.

Not using this add-on until e10s support is added Rated 4 out of 5 stars

The only add-on that still doesn't have e10s. It's been a while, so I'm gonna have to disable it and live without it.

This user has a previous review of this add-on.

Support for e10s/Electrolysis

Hi there, we are sorry to hear that you've decided to discontinue usage of the Xmarks add-on, but we do thank you for providing feedback regarding your desire to see support for e10s added.

Good Rated 4 out of 5 stars

Need Firefox e10s(Electrolysis) support.

multiprocess Firefox (e10s) support Rated 3 out of 5 stars

I have been using it for years without major issues but what about multiprocess Firefox (e10s) support? It is the only remaining add-on (among few I use) not supporting it. Would happily enable e10s support now but can't without working Xmarks. With multiprocess supported it would be 5 stars but without it is can slowly become history.

New review with updates Rated 5 out of 5 stars

See my old review first (permalink: https://addons.mozilla.org/en-us/firefox/addon/xmarks-sync/reviews/818201/)

The issues I had were related to having syncing turned on while logged into either FF or Chrome. Anyone who is having issues where you get duplicates all over, denesting/nesting errors, and all kinds of weird stuff causing you to have to constantly restore, it's absolutely caused by be logged into the browsers profile and syncing is turned on.

And to Alex E. below, I think when the developers say the issue is caused by running multiple sync tools they mean even the built-in ones. If you login to Chrome or FF you MUST turn off bookmark syncing in the respective browser option settings.

Gets 5 stars now with that in mind. Though I would STRONGLY advise that the Xmarks team make it known that even the syncing which is a builtin part of each browser will break the addon.

This user has a previous review of this add-on.

Hayatimi kurtariyor Rated 5 out of 5 stars

Bazen firefox bazen baska bir tarayici kullanmak zorunda kaliyorum. Birinde kaydettigim degisikligi digerinde yapmak cok zor. Ama xmarks yer imlerimi, otomatik yaparak istedigim tarayici rahatlikla kullaniyorum. Hayatimi kurtariyor.

Absolutely horrible. Rated 1 out of 5 stars

IN RESPONSE TO THE DEV: My problem was most definitely not caused by multiple bookmark syncing tools running. I attempted using the troubleshooting page prior to making this review and the issue continued for several days after.

I'm giving Xmarks 1 star only because I can't give it zero. It simply fails to do the one thing that native browser syncs can't automatically do, which is keep my bookmarks straight across multiple platforms. Since I have installed it, it has been necessary to go into the app daily to straighten out the mess it causes. Bookmarks get moved, duplicated, and de-nested. At this point, I'm removing Xmarks and I'll just manage them using the import/export tools in my browsers.

The symptoms you have mentioned here relate to running multiple bookmark syncing tools simultaneously. Please see our helpdesk here on troubleshooting your issue - https://helpdesk.xmarks.com/troubleshooting/duplicate-bookmarks-2/. If you continue to see issues, feel free to open a support ticket.

Incompatible With Multiprocess Rated 3 out of 5 stars

Firefox is rolling its new extension APIs and multiprocess. Please port your Chrome version over. Right now I cannot use this addon any more on Firefox with multiprocess enabled.

Freezes your screen, prevents browsing Rated 1 out of 5 stars

It was good once. Now, it constantly runs into syncing problems and freezes, asking you to log in. Problem is, you can't if Xmarks has frozen your screen.

Now, you can no longer contact Xmarks customer support, which immediately sets alarm bells ringing, as they now fob customers off to time consuming `forums'.

Xmarks support has not changed. If you are seeing technical issues, please open a support ticket - https://buy.xmarks.com/supportticket.php?lpnorefresh=1. This link is available on our support pages.