Problem

Unable to edit or add icons to Tools Error "InvalidArgument=Value of '7' is not valid for 'SelectedIndex'. Parameter name: SelectedIndex" occurs when attempting to pick icon to add to tool using Workspace>Customize utility.

Solution

Go to location defined by MS_USERPREF variable. Check for duplicate copies of preference file customize.xml. If no duplicates exist removed the customize.xml file. This creates a new customize.xml using Workspace>Customize interface.

See Also

http://communities.bentley.com/products/microstation/w/microstation__wiki/creating-tool-icons.aspx

https://communities.bentley.com/products/microstation/w/microstation__wiki/8671/restore-microstation-to-factory-defaults