When I open encrypted files via File Explorer, they all open fine, however both Office 2010 and 2016 are installed and Axcrypt always defaults to open files in Office 2010, not 2016. Is there a way I can set it to open in the latest version?
This is not AxCrypt which determines what app is opened. It is governed by windows file association. If you decrypts the file in question and then double click the Word file, it will open in the same version of Word as with AxCrypt. It is also unusual to have 2010 side by side with 2016. Probably the file is a legacy .doc file, not the newer .docx.