How to fix “Input string was not in a correct format” when using calculated date columns in a SharePoint / WSS list calendar view

When I recently tried to create a new SharePoint / WSS calendar view on a list that uses calculated columns for the both the start and end dates, I was greeted with the following error message:”Input string was not in a correct format”

After quite a bit of trawling the web (hence this blog post), it seemed to be a known issue in certain version of SharePoint / WSS. This particular server was already at SP2 ( so I decided to go ahead and install the latest CU - currently August 2010 (

After installing the CU, rebooting and running through the farm configuration wizard, I recreated the calendar view and this time everything worked perfectly.

Here’s a handy reference to the available SharePoint hotfixes and version numbers.