Dimension Treeview does not display all dimensions in Excel

Symptoms
In Excel when displaying the metadata treeview some of the dimensions do not display correctly.

Cause
Incompatible language settings.
Some languages (Turkish for example) are incompatible with the metadata xml file and prevent it from being read correctly.

Solution
In Control Panel, Region Settings change the Regional format to English (UK or US).
You may need to reboot the pc or at least restart Excel.