Tech Tips: What’s the difference between DOC and DOCX files, and which should I use? |

Tech Tips: What’s the difference between DOC and DOCX files, and which should I use?

Question: When working with documents created with Microsoft Word, I see files with a .DOC extension, and others with a .DOCX extension. What’s the difference? And should I prefer one over the other when I’m creating documents?

Answer: This is an important question, and a seemingly simple question; unfortunately, it has a long and complex answer.

As background, files you create with Microsoft Word have a file extension (that is, a part of the file name after the final period in the name, like “My Dog Information.doc” or “Sunday’s Memos.docx”).

This extension tells the operating system to load the document in Microsoft Word when you double-click on the file, based on associations between extensions and actions that you can modify in Windows or OS X (although you generally won’t modify these associations).

It may seem odd that Microsoft Word has two associated file extensions, but there’s a history here.

When Microsoft first released Word, it stored the contents of the document (the text, formatting information, images, fonts, and more) in a file with the extension .DOC. The resulting file that you stored on disk contained information that was proprietary to Microsoft, and its exact format (in terms of the storage of the information in a disk file) was private, difficult to work with and fragile.

Microsoft did document the format, so that other applications could read and write files in Microsoft Word format, but it wasn’t easy. In addition, if a .DOC file was damaged on disk, perhaps as part of a transfer, it was ruined. Even a single byte in the wrong place caused .DOC files to be worthless piles of bytes.

In 2007, Microsoft revised the file format, and made many changes that were all for the good.

Microsoft Word files were now stored in a standard ZIP file format, the file format was simple to understand and document, and any application could easily create files that Microsoft Word could load (and could open and edit Microsoft Word documents).

To discern between the old-style files and the new ones, Microsoft changed the default file extension from .DOC to .DOCX.

Starting with Microsoft Office 2007, the default file format (that is, the format Word used when creating files) was the .DOCX format, although you had, and still have, the option to create and/or load .DOC files.

The main advantages of the new format are that it is far easier to repair a damaged .DOCX file because of the way it’s stored on disk, and that a given .DOCX file is generally far smaller than the corresponding .DOC file would be.

This makes storing and transferring/emailing .DOCX files easier.

Which should you use? Clearly, the .DOCX format is simpler, safer and smaller. Given the choice, use it.

If you’re worried about folks you share documents with being able to open or edit the documents, it’s worth noting that Microsoft created tools that allow older versions of Microsoft Office to be able to work with these file formats, even though they can’t create the documents themselves.

By the way, it’s worth noting that Microsoft made similar changes for Excel and PowerPoint documents in 2007: .XLS files because .XLSX, and .PPT files became .PPTX files.

In each case, the new file format is smaller and safer, and you should use them if possible.

Which Anti-Virus Software is Best for Windows 10?

Q: I’m using Windows 10, and haven’t really thought much about which anti-virus software I should use. I assume there’s some protection built in, but for Windows 7 I used Norton Anti-Virus. Should I install Norton at this point, or am I protected?

A: Well, one thing is for $#%@ sure: You need to use some sort of anti-virus software with Windows. No way around it. You really need something to protect you from the “bad guys.”

Unless you your browsing pattern is far riskier than most, you don’t need to spend any money to get that protection, however.

You could pay for Norton Anti-Virus, AVG, Avira, Panda, or one of the many other anti-virus suites out there, but in each case, there’s no point. And in each case, you end up with more “stuff” than you need.

You don’t need registry cleaners, uninstaller, email monitoring and more — these end up just being extra “crap-ware” on your computer.

What you need is a good anti-virus software, and Windows 10 includes just the thing in its default installation: Windows Defender. Let Windows do its own thing, and you should be fine.

In recent tests, Windows Defender performed well compared with other anti-virus products, and it doesn’t slow down or “gunk up” your computer; best of all, it’s free and doesn’t take any effort to use.

We’re fans of Windows Defender, and recommend it to most users.

On the other hand, Windows Defender is not enough.

You also need to ensure that you don’t get infected with other types of malware. To ensure that you’re covered against all types of exploits, you need software like Malwarebytes, from

This software, worth its weight in gold, helps you find “Potentially Unintended Programs” (PUPs) and other junkware.

The free version of Malwarebytes scans only on demand (when you ask it to) — it’s well worth the yearly subscription cost to have the scan happen in the background, as you use your computer.

Even if you don’t want to spring for the yearly cost, however, it’s worth installing and using Malwarebytes regularly to ensure your Windows computer is malware-free.

Doug Behl and Ken Getz spent years answering technical questions in private, and are minimizing the questions by pre-emptively publishing the answers. Hear Doug and Ken’s tech tips on KNCO radio weekdays at around 8:21 a.m. and 5:38 p.m.; find full write-ups including links to the products they mention at Submit your own technical questions to

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