Duplicate calendar entries on iPhone

Wish I could help, except to say that my experience is identical, including going in to Usersname > Library > Calendars, moving everything out, and trying to move folders back in one by one to see if this is the source. No, every new entry i Make in ICal on my Mac is subject to duplication and multiples on my phone, often 3 or 4 at a time, and it seems random: some calendars, some events, different numbers of repeats. This is one big bug, and Apple is losing me here.

Same problem on my iPhone 4s and I have iCloud disabled. I'm seeing duplicate calendar entries. When I try to clean them up by deleting the extra entry on my iPhone, the entire appointment disappears from iCal on my Mac after syncing. This means that I have to be very careful about deleting a duplicate on the iPhone because it means I may lose the appointment altogether on my Mac.

This problem must be fixed.

I don't understand why entries which have been deleted from iCal appear on my Touch.

Delete something from the Touch, the deleted entry is not in iCal and not in the Touch, then it magically reappears after syncing with the Replace information on this iPod option checked! It's not in iCal after syncing but it's on the Touch.

C'mon Apple. You're treading in Microsoft territory with this kind of lousy programming.

I too, had the same problem. I was only sync'ing via iTunes, not MobileMe, not iCloud.

My problem: something was corrupted in iCal, but it only showed up on the iPhone, not in iCal.

The fix (summary): export the data in all iCal calendars, create new iCal calendars, import the data into the new calendars. Sync only with those new ones.

The fix (details):

On iCal: export each calendar, one by one, into .ics files. Still on iCal, create a new calendar for each one of the ones exported. Name it something different, for example, if the original was "holidays", then make the new one "holidays_recreated". Import the old data into the newly created calendar.

On iTunes: connect the iPhone, and go to "Info" for your phone. Uncheck the box to "Sync iCal Calendars". Say 'yes' to remove / delete the calendars on your phone. Sync or Apply it. Then check the box to sync only selected calendars. Select the newly created calendars. Don't sync the old calendars with the original names!

On iCal: delete the old calendars. (I have not gotten brave enough to rename the new calendars to the old names. I'm fearful of remnants lying about that will make this error come back.)

I spent 1.5 hours on the phone with Apple Support. I bounced back and forth between iCal and iPhone technicians. Finally, a kind iPhone specialist had mercy on me and we experimented until we found something that worked to fix the problem. Neither one of us knows what the exact cause was.

You are not crazy! That's what I can tell myself now, after seeing these posts - I have the exact same problem as you, TheChangeMan.

After a lot of experimentation, I discovered that for some reason, there ARE duplicate entries in the 'screwed up' calendars, but iCal on the Mac does not show them. I even went so far as to restore my phone as a new phone, which ensured there were no calendars whatsoever on the phone. But...once I synched with iCal via iTunes, the duplicates re-appeared, only on the phone.

I also tried this: 1) created a new entry in iCal on the Mac, 2) changed it (renamed and set it to a later time in the day), 3) synched with the phone. Guess what? The original entry (i.e. "New Event") and the changed event both appeared. It seems like the phone is picking up every version of a calendar entry.

Next I deleted the test entry I had just made in iCal on the Mac, synched with the phone again, and lo and behold, that entry and the duplicate were still on the phone. The synch is not synching correctly, apparently, and is picking up every changed version of an event from iCal on the Mac (even though the Mac does not show them, and operates correctly). All the evidence points to this being a bug.

Will try the export/import tip you mentioned above, cajun_gal. I'm so ready for this to be resolved!

Help!!! I have the same problem!

I tried the suggestion by cajun_gal, followed the instructions exactly, and the entries seem to keep on proliferating on the phone, but only one appears in ical. I also keep deleting one changed entry, and it keeps appearing in ical, even though I deleted it from everywhere! What is going on? I tried deleting the ical cache and the preference file, and reset the sync data, all to no avail. I think you are right, purdyboy, but I can't see a solution!

I think I finally solved it! Or at least, it seems to be syncing properly now, with no duplicates. I conclude that it has to do with the beastly icloud, somehow.

Some time back I thought I would try icloud to see how it works, and synced the ical calendar with the Mac, (but not my phone or iPad). Then I decided it was too risky, so I stopped it, only to find that it kindly deleted the calendar from the Mac. I restored it from a backup which I had taken, and then the duplicate problem happened on the iPhone. I did once also try icloud on the phone, but I stopped that.

The problem seemed to be solved when I signed out of icloud in the icloud part of the system settings of the Mac. Once I'd done that and restarted both the Mac and the phone, it all seemed to be OK. It would seem that you can go offline, tell it not to sync with icloud, but it still goes on doing it. There's a bug somewhere and Apple don't seem interested in fixing it.