is an inserted project, and the default duration units cannot be set. To change the default duration units for the inserted ...

is an inserted project, and the default duration units cannot be set.  To change the default duration units for the inserted project, open that project. On the Tools menu, click Options, click the Schedule tab, and then click a duration unit in the 'Duration is entered in:' field.
English
English (United States)
日本語
Japanese
한국어
Korean