I always get an error message saying that it fails to upload a calendar item. The problem started when i updated from version 10.3.2619.0 to the most recent version. So with version 10.3.2619.0 there was no problem. You find a screenshot as an attachment.
sábado 20 diciembre 2025 :: 1635hrs (UTC +0100)
I regret that I am not able to help so here is a translation of
your screenshot for the use on someone who can
Calendar folder synchronization
Failed to upload item “Kristof questions about wall between house and garage”.
You can choose to delete the item locally or ignore the error. If you choose to ignore the error now, the item will be attempted to be uploaded during the next synchronization.
The server returned the following error: Bad Request.
The destination folder was [email protected]/Agenda.
What action do you want to take?
Use this option for all issues during the current synchronization.
Delete item To ignore
skybat
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Exactly the same problem here. been happening for about a week.
“Synchronization of folder MViCal
Failed to upload item “ECC Send FM Report to EC members”
You may choose to delete the item locally or ignore the error. If you decide to ignore the error now, item upload will be attempted during the next synchronization.
The server returned the following error: Bad Request.
The target folder was [email protected]/MViCal.
Which action do you want to take?”
In addition, the problem calendar item appears duplicated in my calendar.
UPDATE. Just started 5 minutes ago
EVERY ITEM IN MY CALENDAR IS NOW DUPLICATED
Past, present and future. (exception, a few one-off entries with no reminder or repeat are not duplicated)
Makes the Calendar totally unusable. At least it hasn’t uploaded the duplicate garbage to iCloud/CalDAV.
This is on Mac, OS 15.7.3. (don’t bother telling me to update to 26.x; that is not going to happen for a while).
Latest emClient version, updated an hour ago (so after the problem exhibited).
The same iCloud Cal works perfectly in Apple calendar on Mac, iPad and iPhone, so nothing wrong with the cal.
The item referenced in the error dialogue has not been changed, so unclear why it is trying to upload it.
Makes the Calendar totally unusable. At least it hasn’t uploaded the duplicate garbage to iCloud/CalDAV.
This is on Mac, OS 15.7.3. (don’t bother telling me to update to 26.x; that is not going to happen for a while). Latest emClient version, updated an hour ago (so after the problem exhibited).
I don’t know what eM Client version you have, but using the latest eM Client 10.4.4293 on Mac from the release history page with Sequoia and also with OS26, the iCloud calendar events sync fine for me personally with no errors or duplicates either when i upgraded eM Client.
You may have possibly had a eg: corrupted account or possibly a database issue prior to upgrading to the latest eM Client.
So I would first suggest if you haven’t already tried to either go to "Menu / Accounts and try removing and re-adding your iCloud account using the automatic account wizard with your current apple app password.
Or if you have been making regular eM Client backups prior to the issue, you could alternatively try restoring a recent backup when you know your calendar was synching ok via “Menu / File / Restore”.
If you still get calendar error synching or more duplicate events, then next suggest to “close eM Client” an try creating a new database incase yours is corrupted in some way by going to the following Mac hidden database folder and renaming it to eg: eM Client-Old . Then reopen eM Client and setup as new and see if that fixes it.
(Mac Hidden hidden eM Client database folder)
“Users\yourusername\Library\Application Support\eM Client”
Lastly if a new database still makes no difference, then there could be an eg: actual Apple Calendar Server problem to whatever Apple mirror server you connect to in your country.
1 Like
Good tips, many thanks.
Deleting the account, restarting, and adding it back seems to have solved the problem.
That’s a relief as I was nervous about renaming the App support folder. I have tens of thousands of messages in dozens of Local folders, and I suspect zapping the app support folder would lose them.
But that was not needed as problem solved.
Thanks again.