Errors in week numbering – Lotus 8.*

In migrating many of our users to Lotus Notes 8, we have recently found that some of them have experienced problems with week numbering, as 2009 has 53 weeks. Week number 53 is shown as week 1. This error carries over to 2010, meaning that week 1 is shown as week 2, and so on. Users using Lotus Notes 6.* and 7.* are not experiencing the problem.
 
This is apparently caused by a setting in the operating system, but can be fixed in Lotus Notes. Here’s how:
 

1. In Lotus Notes, open File -> Preferences, then expand Calendar and To Do, and select Regional Settings like so:
   
2. Then move the radio button from “Use my operating system regional setting” to “Always use the ISO standard” like so:
   
3. Accept the warning that some settings do not take effect until you have restarted Lotus Notes.

That has solved it for me, and for the users that have experienced this problem.