UIAutomation not finding elements on some machines

Hi,

I'm using the UIAutomation framework in my application to read the url from Chrome browser. the principal is to find the URL search bar and read the text from it.

I'm using the following condition:

 Condition nameCond = new AndCondition( new PropertyCondition( AutomationElement.NameProperty, "Address and search bar"),
                                          new OrCondition( new PropertyCondition( AutomationElement.ControlTypeProperty, ControlType.Edit ),
                                                           new PropertyCondition( AutomationElement.ControlTypeProperty, ControlType.Text ) ) );

it was working fine for long time now, and still is, but suddenly on some machine the element is not found. I looked both in UISpy and Inspect on such machine and it seems like part of the elements tree is missing or not recognized.

I tried to compare chrome versions, win os, .NET, but couldnt find any reason why it fails on some machines...

any idea??