Varkha has the symptoms dead on. I was missing the + to add new appointments, events appearing and disappearing randomly.
I upgraded my wife's 3GS to iOS 6 after resolving my issue, and hers syncs to the same calendars I use, and she had no problem.
ArtSpot mentioned the Do Not Disturb feature and I did play with that right after upgrading and wonder if it caused the issue. I'm hesitant to play with it again.
I had the same issue, all my exchange calendar entries disappeared after the upgrade. Removing the complete exchange account from my iphone, rebooting the iphone and adding the accound again (with a different name) solved the issue for me. It just took some time to reload all the email and calendar entries on my iphone.
I think I'm headed to the Genius Bar to get this resolved! I have a slew of "New Events" showing in my Calendar on my iphone4, but nothing syncs from my MacBook Pro Calendar, and no "+" to add a new event. My Calendar on my MacBook is the only one completely up-to-date with both my manual entries and my Subscriptions to other calendars. My online Calendar on my icloud only show certain types of entries...it doesn't include any of the Subscriptions that my MacBook Pro Calendar shows (and iphone USED to show). I too have spent the better part of a weekend day updating and then trying to troubleshoot!!
Yes, same symptoms as me. I thought it must be a one off so I foolishly tried updating my work iPhone 4 at the weekend and I had the same issues again but the restore to fix the calendar went horribly wrong leaving the loading screen superimposed and flickering over the top of the normal interface... Both phones are now ok after setting them up as new phones but what a hassle.
I have the same problem
After upgrading to iOS 6, and waiting a day or 2, my 64gb iPad notified me that I was running out of storage capacity.
Meanwhile, the Calendar app was not working / kept crashing (the only account syncing calendars was my iCloud account). If I try turning off calendar sync through the iCloud account, it just says "Turning off callendars..." forever!
When I plug in my iPad to my macbook, and go to iTunes, I noticed that the "Other" storage space was very high. Therefore, I investigated this further. I downloaded an application off the internet called iExplorer. I broswed my iPad backup using this software to see what was taking up all this space.
The iPad file taking up all this space was a Calendar.sqlitedb-wal file - taking up 9.0GB.
I found the file in Finder in the iPad backup location (~/Library/Application Support/MobileSync/Backup/.../). The file name was 697bb4986e40a4a8b55bf5b9e3cc0d375c062770
Maybe this info can help the engineers sort out this bug
I'd noticed my calendar entries on my iPhone5 not syncing to cloud and I then lost ability to add new entries on phone. I tried the tips here (not restore!), and then resorted to deleting my iCloud account on the phone, then re-entering it. I've got the + back for calendars now, and it's picked up my iCloud entries (but I lost earlier the entries I made on the phone which never got synced up to iCloud). Definitely some problems here!
Yes I did.
Usually, when I tried to delete my iCloud account, it would freeze and not do anything for over 10-20 minutes. So I would close the Settings app.
However, I decided to try and delete it over night. So I pressed "Delete the account" and left it over night. Woke up in the morning and the account was deleted.
When I re-added the account, all was good.
Similar problem here - but ONLY on iPad; iPhone4s seems to be working just fine, syncing with Google calendar perfectly. Further on iPhone I can turn calendars on and off with no problem for Google and iCloud and they work.
On iPad it is a disaster - no calendar syncing, cannot turn on calendars for either Google or ICloud - just sits there saying "Turning on Calendars". Further, if you try to set up a Gmail account it will ONLY do so if you only specify mail, adding calendar or notes stops it working - just says "adding account" for ever.
This is clearly an iOS6 issue, let's see a fix please!
I posted earlier in this thread that I was having the same issues and my iphone4 was pretty much non-functional...so I went in to see the Geniuses yesterday, and was told that I had a number of corrupted apps that was causing the issue...the ios6 update was coincidental they say, but I believe it was a combo of both, since the Calendar never worked after the update. Anyway, they did a complete Restore from my icloud backup, and now everything is perfectly fine. I had a ton of photos and apps, so it took a while to get everything back in place. I was amazed at how well the icloud backup worked, it restored all my settings with no issues.
If you're not comfortable doing this at home, I highly recommend a trip to the Genius Bar to have them handle it, and make sure you have a recent icloud backup before going! I spent about 2 hours there, and then left to have the rest of my apps and photos download throughout the evening. Hope this helps!
There is definitely something not quite right about iOS6.
I am an IT Engineer, specialising in Macs, and I can normally get iCloud sorted for myself and my clients, but Calendars are not syncing between my iPhone 4 and iCloud.
Contacts and emails are fine, but not Calendars.
If I logon to icloud.com, this is not showing the updates I am doing on my iPhone calendar. And also not the other way either, if I put in an appt on my iMac, it does not sync to the Cloud.
Prior to iOS6, all was perfect.
Come on Apple - there is something wrong- we need a fix and QUICK !
Sorry to hear others are having problems.
Upgraded to iOS6 on iPhone4s and iPad 2. Calendar did not act properly after that - many of you have described some or all of the problems I experienced.
I restored to factory settings BOTH devices, as new devices.
Set up exchange.
Email works fine.
Calendar (google) loads fine and then disappears. I click on "show all calendars" and it appears. Then disappears. This happens over and over and over.
Same thing is now happening on my iPhone.
I had been setting up calendar via m.google.com exchange per instructions I found on the internet. I have fixed the problem by setting up my email and calendar by clicking on "GMAIL" not Microsoft Exchange when setting up account (in settings). Good luck!
I was too happy.
Email and calendar now work fine, true, but NO CONTACTS.
Finally gave up and made a Genius appointment. Turns out something had corrupted the core software, hence restoring from backup just reinstalled the problem. The fix was a DFU reset back to factory status. The nice young man (kudos to Shaun Hilyer at the West Quay Genius Bar) showed me how to do this myself.
All now fixed, although the moving all data out he hard way before doing this was a pain - inherent weakness of iOs deign!