You recently purchased an iPad and started syncing with Outlook, along with your iPhone. Some where recently it stopped syncing new items between those devices. You have rebooted all those devices and tried disabling any add-ons.
You can reset your sync history, disable 3rd party Outlook add ins, sync content in a new or different Windows user account, and reinstall Apple mobile device support and iTunes. First two solutions are fairly quick, while latter two are more time consuming. They are all worth trying until your problem is resolved.
You can view a iPhone, iPad, iPod touch: Troubleshooting contact and calendar syncing via USB on Windows article from Apple that has instructions to perform all solutions I provided. You can try a following configuration.
For Calendar content:
- In iTunes, select an option "Do not sync events older than 30 days."
- Select a iPhone, iPad, or iPod touch in the left-hand column in iTunes.
- Click the Info tab.
- Scroll down to Calendars and select that option.
- If the sync is successful, the issue is with an event older than 30 days.
- Try reducing the number of days to see if the issue is resolved. If you reduce the time frame to 1 day and the issue persists, you know the issue is with an event in the future.
Check to make sure iTunes Outlook addin is enabled and any 3rd party add-ins you may have installed for your calendar. Also, check to make sure you don't have multiple calendars inadvertantly setup in Outlook. You can try to restore your computer to settings before you started having this problem.
A Windows 7 system restore might fix your issue. Click your "Start" button and in "Search" box, type "system restore". Click System Restore in list of results.
Try to pick a date before your problem started occurring. Yes it will revert back changes made to Windows since then. That is a point of doing a system restore.
You can restore Windows to a state before you began having a problem and then make any necessary changes that hopefully won't produce your problem. Yes it's up to you, but you can certainly uninstall and reinstall iTunes. Please read a removing and reinstalling iTunes on Windows 7 article from Apple support that has proper instructions.
Make sure to remove all software associated with iTunes as specified in that article. Downloading iTunes newest version and installing is recommended. Also, there maybe a problem with message class property on your calendar items.
A some Outlook calendar events might not sync article from Apple has instructions. An Outlook plugin may have renamed your Outlook calendar entries message class property which will cause them not to sync. You can try a following possible fix.
Export your entire Calendar to a .pst file. In Outlook go to "File" then choose "Export". Then change a view in Calendar to "View All" and delete all items.
Test with one appointment. If a sync works with test appointment then import all items back in to your calendar again. In Outlook go to "File" then select "Import" and move all items to an existing calendar or seperate calendar.
Also, it has been suggested that your problem may have to do with recurring appointments that have no specified end date. They stated that adding an end date would fix your problem. If you have a recurring appointment or appointments that you have created in your calendar.
Open each individual appointment and set it's end date to a future year. Test by syncing. There might be a rogue calendar appointment causing your problem.
If you decide to rebuild your calendar, and you don't have that many appointments you might want to import them one at a time until you find your culprit appointment. You could also try importing batches at a time until you find a batch of appointments that won't sync. Creating a new calendar and starting a new, while making sure you back up your appointments if you need them might be your best bet.