How to Reduce the Size of Your Outlook Calendar
If you have limits on the size of your Outlook mailbox, you can free up space by cleaning up your Calendar. Determine a time frame for which you no longer need the invitations, attachments or related messages that can be associated with Calendar invitations. View your invitations and delete those you don't need. Be careful not to delete recurring events with meetings in the future.
Open your Outlook application. From the "View" menu, select "Arrange By" and choose "Categories."
Sort your meetings to determine which past meetings you can safely delete. Deleting numerous invitations reduces your mailbox size significantly. Be careful you do not delete recurring events with end dates in the future or you will miss meetings.
Click on the "Fields" button. Choose to select fields from "All Mail" fields. Scroll down the list and select "Size." Then, click on the "Add" button to add "Size" as a column so you can list your calendar items, including file size.
Click the "Calendar" button. From the "View" menu, select "Current View." Click "By Category." Click the "End" field to sort your invitations. View and delete the invitations you do not need, particularly the ones that are the largest.
From the "View" menu, select "Current View" and then "Day/Week/Month" to change the view back.
Look for other email messages related to the meetings you no longer need. On the "Tools" menu, select "Mailbox Cleanup." (Click "View Mailbox Size" to see your current usage. Click "Close.")Find other items related to your Calendar that you can delete by clicking "Find items older than 90 days" and clicking the "Find" button. Delete as appropriate. To find large items, select "Find items larger than 250 kilobytes" and enter a number. Delete or move items to an Outlook data file as necessary to reduce your mailbox size.
Select "Mailbox Cleanup" in the "Tools" menu. Click "Find" and look for "Appointments and Meetings." On the "More Choices" tab, under "Size," select "Greater Than" from the menu. Enter a value in the box to right, for example 500. Again, delete or move items.
Click on your "Deleted Items" folder to take another look at the messages and invitations you are preparing to delete. Right click on the "Deleted Items" folder name and select "Empty Delete Items Folder."