Windows 10: MS Office 2003 and Windows 10

Office 2016 will definitely open 2003 doc files. No problem there.

It is a one way street. ..... New Office will open files made by older Office, but not the other way around.
Foe example, doc files created by newer Office Word ( 2007 and higher ) will have , by default, docx file extension.
Office Word 2003 will not be able to open that. It can only open doc file extension. But New Office will have no trouble opening doc file extension.

 

If you have office 2003, you can download a free upgrade from MS here:
Download Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint File Formats from Official Microsoft Download Center
It will let you open .DOCX files.
it will also upgrade office 2002 (XP) to 2007

Sven

 

I also have Office 2003 running on several machines (as well as a couple of VMs too) with Windows 10. No issues at all. One of the machines is a netbook with only 1.5G of RAM. Word and Excel 2003 snap open very quickly, much faster than Word or Excel 2013 on my machine running an i7 with 16G of RAM.

If you can't get Office 2003 working under Windows 10, as an alternative try the free LibreOffice. It's a very good office suite that is very close in compatibility to MS Office. It even reads and writes MS Office files.