Caldav: Failed to upload item Conflict(Conflict)

A customer of ours is getting an error everytime emClient is started that it cannot upload an item due to the error: Conflict(Conflict)

I have seen this error before when I snoozed an appointment but I’m struggling to recreate that and didn’t take logs at the time.

We are using the Zimbra platform and I have CalDav logs from the user if that’ll help work out what’s causing this.

Hi, can you please make a screenshot of the error message you’re seeing and send it with the logs to [email protected]?
Also what version of eM Client are you currently using?

Thank you,

Hello, do you have solved your problem ? I have exactly the same.  Thx.

Hi Eric, this topic is almost a year old, can you please be a bit more specific and describe the application’s behavior? What version of eM client are you currently using on your computer, can you please check the exact version number in Help > About?

What mail service are you using with eM Client, are you also using a Zimbra account as did Andy?

Thank you,

Hi Paul,

I use the last version 6.0.21372.0, and effectively I use a zimbra account.

The message is the almost the same. It says :
Failed to synchronize “” : Conflict(conflict).


Hi again Eric, can you please make a screenshot of the error and submit it to us here on the forum?
Also, when the error occurs, please switch to the Log tab in Operations as well, copy the content of the log and submit it to us here on the forum with the screenshot.

Thank you,

Hi there,

I’m facing the same problem with a colleague. The following error message came out :

Translation : Fail to upload item
The item has not been uploaded to the CalDAV server. Error : Conflict.

He then clicked on the “Skip the upload” button (the one in the middle), and the error message never came out again. Like Eric and Andy, we’re using Zimbra. Do you have any idea what this could be due to?

Thank you

Hi Matthieu, thank you for reporting this, I believe this can be connected to an already updated calendar event/task item on the server, for example if a reminder was set and dismissed on another device, eM Client may have thrown out a task reminder on startup and since the reminder was already dismissed conflict may have been thrown.

In case this is a similar scenario you should be able to resolve the conflict by defining which event is more up to date, in case of an issue due to reminders, you should be able to resolve the issue by using any of the selected options for the current synchronization process.

What version of eM Client are you currently using on your computer, can you please check the exact release number in Help > About?


Hi Paul,

Thank you for your reply.

The version of eM Client I’m currently using is 6.0.21372.0

I managed to reproduce the issue. Here is what I’ve done :

  • I created a meeting with a 15min reminder
  • I received a notification about this meeting on my mobile and I dismissed it
  • Then, using eM Client, I received the reminder and dismissed it again => the error message came out then
  • I clicked on Skip the upload and the error message never came out again

Is there any way to avoid this message to come out now that I know where it comes from?


Hi again Matthieu, this unfortunately the case I’ve mentioned, this only occurs when in between synchronization processes as the calendar event synchronized with your mobile device and your computer both contain information about the reminder and run the reminder at the setup time, however if you dismiss the reminder on your mobile device the information are not immediately updated on your computer, as the sync is run once in X minutes based on your setup in the application settings.

Adjusting the time to minimum is however not recommended as this would mean eM Client would be resynchronizing your calendar each minute or less.

We’re currently working on improving the behavior for reminders in future releases, but it is unfortunately not possible to avoid using the current settings.


Thank you Paul. I’ll try to deal with it then. The message doesn’t come out anymore once I’ve clicked on Skip the upload button anyway.


Hi Matthieu, if you’re aware that the conflict was thrown due to the reminder, you can use any of the options, as this should cause no issues to rewrite local/remote instance of the task.

Make sure to let us know if you come across any other issues or questions about the application, we’ll be happy to help.

Thank you,