Symptoms

'Edit in Office' opens as 'Read only' in Firefox after Office Suite upgrade. In contrast, it works fine in Internet Explorer.

Cause

This can happen if you were using Office 2007 previously and then upgraded to Office 2010. The application paths are different in Office 2010.

Resolution

Attachment extensions need to be updated in Firefox's WebDAV launcher Options:

1. In Firefox, click Tools > WebDAV Launcher Options
2. In the pop up window, enter the extension type eg. doc, xls, etc. and browse for the correct application to handle the file extension.
   Newer version of the WebDAV launcher has an auto complete function which can identify the latest version of your Microsoft Office. You need to click on the 'Auto' button after you have entered the file extension.