Recently a client of mine decided to pull their calendar off of google, where it was held hostage and they would have to log in to a separate window to access it. The had moved to office365 6 months prior and were our pilot in what we can do with office365 for our other clients. We set them up with a calendar from the default list options, and setup permissions. Adding the calendar to their outlook was a few easy clicks.

To add a sharepoint calendar to outlook:

1. Browse to the sharepoint portal – yourdomain.sharepoint.com
2. Login with your office365 credentials
3. Click the link in the nav bar on the left for the calendar
4. Click the Calendar tab at the top
5. Click “Connect To Outlook” in the ribbon
6. Click Allow
7. Click ok.

And Bam! sharepoint calendar in outlook!

All appeared well. That is until my import of their calendar entries completed.

You see, in order to get their entries out of their google calendar and into sharepoint, I had to export the google calendar as an .ics file to my computer, attach it to my outlook, attach their sharepoint calendar to my outlook, copy the entries from local to sharepoint, and let it sync away.

The next day they called and were getting errors that the list was too large, and couldn’t even open the calendar in outlook. After some quick googling, it turns out there is a hard list limit in Sharepoint Online of 5,000 entries. They were at 5,326. Microsoft says this is to reduce the load on the servers from syncing large lists. Since these are Microsoft servers in the cloud, you cannot change this limit.

Then another problem. I couldn’t batch delete the items since they were over the limit, and deleting the calendar altogether wouldn’t work either. I ended up manually removing enough entries to get them under the limit, then deleting the calendar and starting from scratch.

I created an archive calendar, with entries from 2006-2011, and a Corporate Calendar from 2012-present. This brought the active calendar down to 1,400 entries, which would give them plenty of room to grow, and we could re-evaluate in a few years, if they were still using this technology.

Calm waters until the next week. Now users, were getting access denied (403) errors. After an hour of troubleshooting on one user’s computer, and no google results, the only thing that I had determined was that on first attach the calendar would sync properly, but after closing and opening outlook, their permissions seemed to disappear. It was the end of the day, so I said I would take a look at it in the morning.

Being the person who can’t stand a problem left unsolved, I went a googling at home that evening. After some google-fu and adjusting keywords, I came across this link:

http://community.office365.com/en-us/forums/152/t/10155.aspx

and used this as a more specific reference for the registry entries:

http://blogs.technet.com/b/heyscriptingguy/archive/2005/05/02/how-can-i-add-a-site-to-internet-explorer-s-restricted-sites-zone.aspx

It turns out that it was a securty issue for internet explorer. Adjusting these registry entries and reopening outlook allowed the sync to run almost perfectly. In one case, the trusted zone security was set to medium, and I had to change it to low.

In the case of mydomain.sharepoint.com the registry should have a dword entry for “https” with a value of 2 in the following locations

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains\sharepoint.com\mydomain

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains\sharepoint.com\mydomain

I created a script through our RMMS system (LabTech) to push these entries out to the computers. All is well.