Microsoft Word can not open OpenOffice .odt files. This is a file format that should not be used any more.
.odt is the old open standard file format that was used before the current Office Open XML standard was implemented. Microsoft began adopting the standard in 2003, but in Office 2007 and Office 2008 adopted the Office Open XML file format as the default
format.
Ironically, most forks of OpenOffice do not support the current Office Open XML standard format. They cling to the decades old standard and refuse to abandon it. However, there is one fork of OpenOffice that
does support the current standard. It is called **LibreOffice**. LibreOffice is the only fork of OpenOffice that should be used. Have the person who sent that ancient file to you update to the current version of LibreOffice so they can make
files in standard format. In LibreOffice preferences there is a setting that tells LibreOffice to use the Office Open XML file format as the default. This setting should be enabled.
Once your correspondent joins the 21st century and gets rid of their ancient software, he or she will be able to share files with the **rest of the world**. Wikipedia misleadingly labels the Office Open XML format a "Microsoft format." The format is an international standard proposed by Microsoft and then adopted by a standards
body representing many interests.