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Duplicate entries


I seem to be getting duplicate entries at times. Sometimes I get over 5 duplicates on one event at one time on my google calendar.

Only way to resolve is to purge my google cal and re-sync and that fixes it temporarily.


CancelBot wrote Sep 18, 2013 at 5:42 PM

Did this behavior occur when you were syncing one or more multi-day appointments? I've seen this before, but it seems to come and go possibly related to multi-day appointments.

english2 wrote Sep 19, 2013 at 12:53 PM

I'm having the same issue with v 1.0.9. I'm using default settings and syncing once an hour. Each time no Google calendar entries are deleted, and half of the detected Outlook entries are recreated as duplicates (a mix of unique and recurring appointments). I'm using Microsoft Office Standard 2010 in French. Below is an example log where 125 duplicates are created. As a very temporary measure I have resorted to running a utility called massdeleteevents.jnlp to remove duplicates from Google Calendar after syncing. Anyone got an idea how to solve this?

Sync started at 19/09/2013 12:00:18

Reading Outlook Calendar Entries...

Found 243 Outlook Calendar Entries.

Reading Google Calendar Entries...

Found 118 Google Calendar Entries.

0 Google Calendar Entries to be deleted.

125 Entries to be created in Google.

Creating 125 Entries in Google...


Sync finished at 19/09/2013 12:01:54
Time needed: 1 min 36 s

jyanes wrote Sep 23, 2013 at 5:48 PM

I ran into this same issue. I am looking at the code now but i was able to confirm that the duplicates occur when syncing against a Primary Google Calendar. If you setup a NON Primary google Calendar, you will not have any issues. The latest version has an issue with the application not showing up in the notification icon bar when minimizing. You can fix this by getting the code and for MainForm.cs setting the icon to the image.

candroulakis wrote Sep 23, 2013 at 7:05 PM

The calendar I sync with is not the primary calendar. It seems to happen with random events but not all. Sometimes, I get 10 duplicates of the same event at the same time. Its not happening consistently with either re-occurring or non-reoccuring events.

candroulakis wrote Sep 23, 2013 at 7:07 PM

Could there be an option to wipe the google calendar clean each time so everytime it will sync all events new? That would fix my individual problem as the only way for me to fix is that I have to delete the google calendar and recreate it again to resync it.

jyanes wrote Sep 25, 2013 at 3:16 PM

I see what you are saying as far as the issue. I tested it further and get the same thing. As far as what you are requesting. I do have a version of the program that would do this. There are some caveats. The only way to wipe/clear a calendar is if it is your primary calendar. In my case, i am already using my primary calendar for something, so i signed up for a new GMAIL account just for my WORK calendar. I then launched the new version of the program, setting up my connection to the new GMAIL primary calendar. The new program will issue a CLEAR of the calendar and then sync all events from Outlook to it. Now it will take a bit longer due to the fact that it has to clear and then push all the events back but its not too bad. Send me a private message with your email address if you want me to share the version with you.

english2 wrote Sep 26, 2013 at 1:03 PM

I've just tested this new version, and it works perfectly for me. It's available here : (take note of the caveats listed by jyanes above before using).

TheJacksonian wrote Oct 22, 2013 at 4:24 AM

I"m having this issue also.
It certainly appears random.

Using Office 2013 / Win 7.

My google calendar is not the primary one.

mca2 wrote Dec 24, 2013 at 9:38 AM

Very nice app but...

Same issue here. I'm on windows7 and syncing to a non primairy gmail calendar. The first few days seem to be ok, but the further i scroll forward in time, the more duplicates. At some point there are 10 to 30 duplicates for all items.

A suggestion: first delate all entries and then re-add them at sync? Might be a bit slower, but prevents all these duplicates.

sjvermeu wrote Feb 5, 2014 at 8:26 PM

I can also confirm this, with a non-primary google account.

I have tried with more recent Google.*.dll files, although this didn't resolve the issue. However, I can only build with .NET 3.5 (at most) for now, so the really last versions of the DLLs I can't use (as those are now .NET4 specific).

A user reported as well that he didn't have duplicates if the synchronization window (i.e. the number of days) is sufficiently low. If the amount of events that need to be synched is around 250, then the problems start occurring. Not sure if this is by accident or not though.

sjvermeu wrote Feb 5, 2014 at 9:57 PM

I believe I have found the (a) solution.

In GoogleCalendar.cs' getCalendarEntriesInRange(), I now use the following settings on lr:
            lr.OrderBy = EventsResource.OrderBy.StartTime;
            lr.SingleEvents = true;
With this in place, synchronization for even large sets of days works fine.

miroen wrote Feb 11, 2014 at 1:23 PM

Hello sjvermeu,

I can not find the GoogleCalendar.cs file.
How do I solve this issue?

miroen wrote Feb 11, 2014 at 2:23 PM

Edit for above post:
I've found te source code but I have no idea how to turn this into a working program...
The potential of this program is great, but it has some issues.

stef_09 wrote Mar 15, 2015 at 12:34 PM

Have a look at
They provide a web app. Free to use, raw interface, but do what you want