Mar 18

Recently was updating my notes using Evernote from my iphone and recieved the following error:

Synchronization failed.
Unknown error u11

After searching google found a few discussions about the problems and some suggested fixes. Not all of these fixes worked, for example logging out and logging back in made no differences.

The consensus of opinion was that the root cause was html with url’s in the note, in particular strange characters in the url. This turned out to be the problem in my case and once the offending characters (% in my case) in the href url was removed the error vanished and syncing went back to normal.

Cannot say this will help everyone with this problem, but hopefully it helps someone. With any luck Evernote can fix this problem in an upcoming release of what is a great application.

written by Obiweb \\ tags: , ,

Array ( ) 22 Responses to “Evernote – Synchronization failed. Unknown error u11”

  1. Paul Says:

    I’m getting this error too and it’s only affecting one of my notes when I update it on my iPhone. I guess this means there are some “offending characters” in there somewhere.

  2. Obiweb Says:

    Can you post the note here and we’ll have a look at it for you

  3. Clif Beasley Says:

    Thank you! The URLs in my notes didn’t have a % sign, so I removed http:// as well as the preceding and following character from the URLs in my notes and voila! it syncs.

  4. Vinko Says:

    I too encountered this error.

    By deleting the note that is pending upload from my iPhone fixed the problem and my Evernote synchronization went back to normal.

    The problem note contained HTML codes but exactly which of the HTML codes caused this problem I do not know. I think Evernote needs to review their note encapsulation for the body of the note to ensure all note content are encoded prior to being stored on the server.

  5. Michael Shearer Says:

    I emptied my trash (where the offending note probably was) and that resolved the sync problem (between comp. and ipad).



  6. Cheeky Says:

    Emptying trash worked for me.

  7. Antonia Henges Says:

    Great blog! I genuinely love the way it? s uncomplicated on my eyes also as the Information are properly written. I’m questioning how i may be notified when a new post continues to be created. I’ve subscribed for your rss feed which will need to accomplish the trick! Have a good day!

  8. Obiweb Says:

    Thanks for the feedback. Let me know if thr RSS does the job for you.

  9. Mike Goitein Says:

    This happened due to a note that was created by copying a page from GoodReader and pasting the contents into a new note. Couldn’t sync until I deleted the note, even though no odd characters were present. Odd.

  10. jan de vries Says:

    When I clip a text it doesn”t appear in my notebook at all anymore. I cleaned up al the old notes (also from the trash), but it still doesn’t work. I am afraid there is no synchornazation anymore. How can I solve this problem.

  11. objects Says:

    That doesn’t sound like a synchronisation issue. Have you tried reinstalling evernote?

  12. John Says:

    This has happened to me also. Not sure why. I have been using the free Evernote for a few months now, but just got round to using a bit more. I created a few new notebooks, and was taking some pictures of timesheet scans and invoices. The error message comes up on both my iphone and my ipad.
    i see that emptying the trash seems to solve the issuer for most, but I rarely use the laptop, in fact i am away from home and just using the ipad as a principle computing device. As a consequence, there is no trash function on the ipad. Any suggestions?

  13. objects Says:

    Check the content of recently added notes

  14. Henri Kardaun Says:

    Kan niet synchroniseren. Melding fout u5
    wat te doen

  15. Ike Says:


    My offending note had the phrase “24/7” in it, which Evernote tried parsing into a hyperlink.

    I deleted 24/7 and replaced it with 24 / 7 — and it synced right up!

  16. Ade Brown Says:

    to be fair I’ve had nothing but trouble from the Evernote service with several bugs here and there on my android phone and iPad. The mac version seems to be OK.

    I find it ludicrous that you have to remember to write your note in a certain way.

    Unfortunately for Evernote I was about to go over this has come at a time when I was considering paying for the service. I’m not sure I should mention the name in here so I won’t, but I’m moving over to Evernote’s newish competitor who I found out of frustration and love. Don’t want anyone to thing I’m one of the other sides employees 😉

  17. Joao Aroso Says:

    Same here. Content of a recent note (last one) has hyperlinks on wired words. Rewrote them and worked fine after.

  18. IGp4 Says:

    I have the same problem on Evernote for iphone!
    I saved a website with an Foursquarebadge and just i become this error!
    I solved this with:
    deleting the notice, clear the cache and trash – and i wondering me – it’s syncing run’s normaly!

    I hope this can help you solved the same problem?
    (Evernote runs on Win 7/64 and iPhone iOS 5)

  19. Steve Says:

    The Evernote Hello app constantly produces this error making it useless.

  20. Malone Guthrie Says:

    Hi all
    I have been getting this error message for a few weeks now, and not been able to resolve it. If the concensus is that it is something to do with html (web clips?), my question is: how do I find out which web clip is causing the problem, I have loads of them!
    Thanks in advance for anyone’s help.

  21. objects Says:

    Not aware of an easy way to find which one. Only suggestion would be to start looking at notes added around the time the problem started happening

  22. Lema Says:

    I am very new to Evernote and I’m getting a similar message:
    “Synchronization failed.
    Unknown error u9” when synching Iphone to my Mac

    I am getting this on several notes, some are just recording (interviews), others are pictures, one note has both pictures and recordings. Some of the recordings have synched, some of the pictures as well. But there are several that are not synching, and they are not larger or much different than the ones that did…

    Didn’t write anything inside so I doubt it’s an ‘offending’ character issue…

    I want to delete and reinstall Evernote as suggested above, but how do I make sure I don’t lose my recordings/pictures on the iphone? it’s my only ‘copy’ for now…

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