My Scientific American column this month concerned a sneaky problem that not many people are paying attention to: file-format rot. That’s when our digital files become unopenable not because their storage media becomes obsolete, but because the software programs that created them are no longer available—or, in the case of Microsoft Word, can no longer open their own oldest documents.

The Word situation is especially bizarre; Microsoft is the curator of the world’s most common word-processing format. You’d think they’d feel some obligation to maintain its ability to open its own documents, no matter how old.

As it turns out, Word can open many kinds of older Word documents—but only if you make a few changes. (Out of the box, Word refuses to open document types that could contain viruses.) Here’s how to proceed.

In Word for Windows 2010, 2013, or 2015, open the File menu and choose Options; click Trust Center, then Trust Center Options. Here, click File Block Settings.

Turn on the Open checkbox for each file type you’d like your copy of Word to be allowed to open. Use the options at the bottom to indicate whether you want Protected view (you can open the document but not edit or print it—safest from viruses) or to allow editing.

Unfortunately, this trick doesn’t help you with the oldest Word files. Documents from the late 80s and early 90s may present you with the “Recover text” option only (you can scrape some recognizable words out, but all formatting and accents are lost) or only a blank screen.