Failed to map parentId to Server

[cjpalermo21]

Which version of floccus are you using?

5.6.0

How many bookmarks do you have, roughly?

20k

Are you using other means to sync bookmarks in parallel to floccus?

No

Sync method

Google Drive

Which browser are you using? In case you are using the phone App, specify the Android or iOS version and device please.

Firefox 144.0.2

Which version of Nextcloud Bookmarks are you using? (if relevant)

No response

Which version of Nextcloud? (if relevant)

No response

What kind of WebDAV server are you using? (if relevant)

No response

Describe the Bug

My own fault - I haven't synched in a month (so I also had to disable the failsafe). I've been using my laptop exclusively.

But, I tried to synch today; and got this error:

Failed to map parentId to Server: xPID9NjMG0Z5 | Last synchronized: 1 month ago

Expected Behavior

The bookmarks should sync without error.

To Reproduce

I simply tried to sync (although, it's been a month since I've last done it)

Debug log provided

• [ ] I have provided a debug log file

[github-actions[bot]]

Hello! :wave:

Thank you for taking the time to open this issue with floccus. I know it's frustrating when software causes problems. You have made the right choice to come here and open an issue to make sure your problem gets looked at and if possible solved. Let me give you a short introduction on what to expect from this issue tracker to avoid misunderstandings. I'm Marcel. I created floccus a few years ago, and have been maintaining it since. I currently work for Nextcloud which leaves me with less time for side projects like this one than I used to have. I still try to answer all issues and if possible fix all bugs here, but it sometimes takes a while until I get to it. Until then, please be patient. It helps when you stick around to answer follow up questions I may have, as very few bugs can be fixed directly from the first bug report, without any interaction. If information is missing in your bug report and the issue cannot be solved without it, I will have to close the issue after a while. Note also that GitHub in general is a place where people meet to make software better together. Nobody here is under any obligation to help you, solve your problems or deliver on any expectations or demands you may have, but if enough people come together we can collaborate to make this software better. For everyone. Thus, if you can, you could also have a look at other issues to see whether you can help other people with your knowledge and experience. If you have coding experience it would also be awesome if you could step up to dive into the code and try to fix the odd bug yourself. Everyone will be thankful for extra helping hands! If you cannot lend a helping hand, to continue the development and maintenance of this project in a sustainable way, I ask that you donate to the project when opening an issue (or at least once your issue is solved), if you're not a donor already. You can find donation options at https://floccus.org/donate/. Thank you!

One last word: If you feel, at any point, like you need to vent, this is not the place for it; you can go to the Nextcloud forum, to twitter or somewhere else. But this is a technical issue tracker, so please make sure to focus on the tech and keep your opinions to yourself.

Thank you for reading through this primer. I look forward to working with you on this issue! Cheers! :blue_heart:

[cowboysmall]

I am experiencing this exact issue - on both Chrome and Firefox.

[marcelklehr]

Hi @cjpalermo21 Thanks for taking the time to give feedback by opening this issue. I'm aware of this kind of error, but haven't managed to squash all instances of it.

In the meantime you can try to trigger a sync from scratch in the settings of the profile that errored. Make sure you have a backup of your bookmarks before you do this, and check your bookmarks for deleted bookmarks that may have come back. You can be sure that nothing will be deleted in this step, though.

This is the button to click:

And make sure to click on save afterward.

I hope this helps. Let me know if this works for you.

[defect-track]

Run into a similar issue floccus 5.6.0, Linkwarden 2.13.1 and latest Brave on MacOS Sequoia:

> 2025-11-14T10:05:12.349Z Filtering out invalid server bookmarks
> 2025-11-14T10:05:12.349Z Generating indices for local tree
> 2025-11-14T10:05:12.350Z Generating indices for cache tree
> 2025-11-14T10:05:12.351Z Generating indices for server tree
> 2025-11-14T10:05:12.352Z { localTreeRoot: 
>      + #2[undefined] parentId: undefined, hash: undefined
>        - #3[hetzner_ddns/hetzner_ddns.sh at master · filiparag/hetzner_ddns · GitHub](https://github.com/filiparag/hetzner_ddns/blob/master/hetzner_ddns.sh) parentId: 2
>  ...
>       Action: REORDER
>       Payload: #670[[ reverse IPv6 DNS]] parentId: 669 Order: [
>       	{
>       		"type": "bookmark",
>       		"id": "671"
>       	},
>       	{
>       		"type": "bookmark",
>       		"id": "672"
>       	},
>       	{
>       		"type": "bookmark",
>       		"id": "673"
>       	}
>       ] } }
> 2025-11-14T10:05:12.764Z Checking deletion failsafe: 0/630=0
> 2025-11-14T10:05:12.764Z Checking addition failsafe: 0/630=0
> 2025-11-14T10:05:12.765Z Checking deletion failsafe: 632/621=1.0177133655394526
> 2025-11-14T10:05:12.766Z Syncing failed with E029: Failsafe: The current sync run would delete 102% of your links. Refusing to execute. Disable this failsafe in the account settings if you want to proceed anyway.
> 

Luckily "Failsave" is enabled to not redo them all gain.

The trick "reset cache" as described above solved it! No bookmarks lost nor duplicated added.

Hope it helps other solving....

[cowboysmall]

"reset cache" didn't resolve the issue for me.

Because I relied on floccus to manage my bookmarks, and because I had lost lots of bookmarks due to this issue, I had to jump through hoops to restore most of my lost bookmarks by taking a backup of the Bookmarks file in .config/google-chrome/Default on one of my laptops where I had not opened chrome in a few days - unfortunately I did not have a backup exported of my bookmarks.

The reason I used floccus was to sync bookmarks across different browsers - I used chrome's sync to sync across chrome instances, but I wanted to be able to easily sync bookmarks on firefox, etc. I definitely do not want to ever go through this process again. I have decided to disable floccus and look for a different solution - in the interim I will go through the pain of manually managing bookmarks by regularly exporting my bookmarks and manually importing them when appropriate.

Thanks very much for floccus - it was a great idea that filled a gap in my workflow, but unfortunately it has not proven to be as reliable as I would have hoped.

[staeglis]

I can confirm the issue. I use Firefox only

[CallMeLaNN]

Ok, this is the most important issue and become a show stopper since sync is the main feature.

I was left this app unused for a few months since last version due to this issue, but this app still on my home screen because I still review it and this is the best choice so far. I come here after the new update doesn't fix the error.

I don't know when and why the error appeared. I think just a couple of weeks used and just add/modify a few bookmarks in maybe 1k imported chrome bookmarks.

My issue is the same as OP but sync between Chrome on mac and on Android. The error is in the Android app.

I understand how difficult is to sync data because I did that before. I hope this app doesn't do it manually but use certain library or framework.

Ok then

I just use RESET CACHE button and it works but not sure if I lost anything, I can't remember the last changes I made in the app.

Please don't use cache or make 3 ways sync, it's incredibly complex. Sync data between two server and client only. Client storage is enough without cache. I might be wrong because I don't know the design but if this error can fix by itself without data loss, it supposedly can resolve the conflict silently without any issue.

It will be helpful if someone can describe the step to reproduce, so at least we can avoid that step for now. Long time haven't sync? Delete one and modify on the other client?

Thanks for the hard work.

[marcelklehr]

It will be helpful if someone can describe the step to reproduce, so at least we can avoid that step for now. Long time haven't sync? Delete one and modify on the other client?

Indeed, figuring out the steps that cause this is paramount. I also have a fuzzy testing setup where I try to simulate wild bookmark tree manipulations to trigger bugs. In v5.7.0 I believe to have found and fixed some mapping related bugs, so I can recommend updating to the latest version.

I just use RESET CACHE button and it works but not sure if I lost anything

Reset cache can only cause some deleted bookmarks to come back, it doesn't make you lose bookmarks :)

I might be wrong because I don't know the design but if this error can fix by itself without data loss, it supposedly can resolve the conflict silently without any issue.

Indeed, that is a possibility. I have taken to the proverb to better "fail early" for now, though.

[marcelklehr]

So, it turns out that in some cases this error appears because floccus persists its syncing state on a best effort basis at most once a second or so. Sadly, Chromium browsers have the habit of killing floccus' background worker that does the syncing mid way through, if it takes too long. Combined with the best effort persistance, this causes situations where floccus has executed some changes but is no longer aware of them in the next sync, which results in the failed to map parentId error.

There are a few ways out of this:

1. One way would be to no longer persist state on a best effort basis and instead persist after each change (at least in Chrome). This would slow down the syncing performance quite a bit.
2. Another way would be, as @CallMeLaNN suggested, to catch failed to map parentId errors and automatically reset the cache before resuming sync. This has the benefit of not slowing down sync, but the disadvantage of deleted bookmarks coming back in some situations.
3. A third way would be to try and portion sync runs as with only a few actions each to avoid the background worker getting killed before the sync is done. This would also slow down sync performance and has the drawback of the prediction being wrong and floccus still hitting this error.
4. Another way would be to no longer sync in a background worker and instead open a temporary popup window for syncing. I believe this would be very annoying to users, but it would definitely solve the issue.

[marcelklehr]

cc'ing @balthanon for input, maybe you have another idea :)

[balthanon]

Do we have any examples of this happening when there hasn't been a long time between syncs? I haven't run across it myself (at least that I'm aware of), but option #1 or #3 could be feasible with some additional checks. Basically only trigger the more robust version of the sync process if we're aware there is likely to be a problem-- it's been x weeks since a sync, the # of bookmarks is significantly different between the server/client, or x number of changes have happened since the last sync (assuming you can get at this before doing a full run); then take the time to run more slowly and do a thorough job of it.

Honestly, I would even personally be okay with a pop up in cases where it has been a long time since a sync has run asking how you want to handle it personally. I have had some issues pop up in the past where old bookmarks got in somehow because I opened a browser I hadn't used for 3 months or 6 months. I'd almost prefer personally that in situations like that Floccus pops up a message asking "It has been x months since you have used Floccus in this browser. Do you want to just download your current bookmark set, sync as normal [triggering the more robust version of sync], or xyz? [if there's a third option I haven't thought of-- maybe something where it gives you a summary of changes that are going to happen, but that would probably be a pain to code]"

Another advantage of doing something like that is you already have a pop up in place at that point that you might be able to use for #4, but it presumably will be reassuring to the end user rather than annoying because you're showing that you're being careful with their data. (And it isn't happening constantly when it isn't likely to be an issue.)

[marcelklehr]

Thank you for your input @balthanon

Do we have any examples of this happening when there hasn't been a long time between syncs?

Yes, the "multiple weeks without sync" symptom is just a proxy for "a lot of changes in one sync". which cause floccus to run over the alotted time that chrome gives the background worker until it kills it.

I've now released solution #2 with v5.8.2 as it is a quick win to avoid people running into this error without knowing what to do with it. The worst thing to happen with this is that an old deleted bookmark or folder comes back. Solution #3 is something I will look into, together with your solution of a threshold of changes in the diff after which the more thorough persistence is triggered.

[cjpalermo21]

So ..... for the non-techies here ... :)

Is there a new version we're supposed to download (5.8.2?) and where can we get that.

I did try to sync again today, resetting the cache first ... same error.

I've basically just begun exporting the bookmarks to html and re-importing them on my other computer, when I need to. Maybe I just need to get a script that does that automatically each day :)

[marcelklehr]

@cjpalermo21 5.8.2 will make it's way to you, usually. Unless you installed directly from github, in which case I would encourage you to update, indeed.

[marcelklehr]

I finally find a way to prevent ~~the browser~~ chrome from killing the worker. Let's see if this holds up.