Hands on with Office Online and Dropbox: A surprisingly smooth combo

Microsoft has been expanding the reach of its Office franchise over the past year, releasing apps for iOS and Android, occasionally even at the expense of its Windows division.

But the latest Office expansion comes inside the browser, where anyone with an Office.com account, free or paid, can now link Dropbox accounts for seamless creation, viewing, editing, and sharing of online Word documents, Excel spreadsheets, and PowerPoint presentations.

That's a huge move for Microsoft, which has just removed a major source of friction for more than 300 million Dropbox users, many of whom aren't willing or able to embrace Microsoft's rival cloud file storage services, OneDrive and OneDrive for Business.

I connected an existing Dropbox account to Office 365 Personal and Office 365 Enterprise subscriptions, and I connected a second Dropbox account to a Microsoft account signed at at Office.com without an Office 365 subscription. Here's how the process works and what you can expect

When I signed in at Office.com today, I saw an announcement like the one shown here, with a link to connect a Dropbox account to Office Online.

That connection went smoothly. Because I have two-factor authentication enabled on my Dropbox account, I had to enter a code to complete the link-up. Dropbox has had some noteworthy security failures in the past, but seems to have moved beyond them.

With the Dropbox-to-Office connection complete, you'll notice two new options on the Office Online New Document pages for Word, Excel, and PowerPoint. The default storage location is OneDrive (with free Office.com accounts or Office 365 Home and Personal subscriptions) or OneDrive for Business (for Business and Enterprise subscriptions). But you can use the drop-down list at the top of the page to change the current cloud storage location to Dropbox and create a new file.

You can also click the Open from Dropbox link in the lower left corner to open a pop-up browser window where you can pick existing Office files from Dropbox for editing.

Inside the Office Online window, you have access to the same editing controls as you would with a document stored in OneDrive. Any changes you make in Excel, Word, or PowerPoint Online are saved immediately.There's no need to manually save changes; in fact, that's not an option.

When you view an Office document in Dropbox, you get a high-fidelity preview of its contents, like the one shown below. You can't edit it from Dropbox; for that, you need to click Open and switch to Office Online. (The Dropbox window is the correct place to rename a file, however.)

To share a document with someone else, you can use the Share buttons from Office Online or from Dropbox. In either case, you get a web link that you can send via email or a direct messaging program.

This linking ability is fairly crude. All Office files shared from Dropbox are set as read-only. Recipients can view the file, download a copy, or open it in their own Office 365 subscription. But none of the OneDrive collaborative editing functions are available for a file stored on Dropbox. You can password-protect a file link if you have a Dropbox for Business account, but there's no way to share a file with specific people, with or without editing rights, as you can with OneDrive.

Despite the rise of cloud storage as a zero-cost feature, Dropbox has continued to grow. This partnership might seem unlikely at first glance, but it's a smart move for both companies, who share a common rival in Google, with its Apps/Drive combo.

I tested the Office Online features with multiple browsers on both a Windows PC and a Mac. I didn't run into any browser-specific glitches, although I found one confusing issue when creating a new file from an Office Online template. To see the template content, I had to save the file, return to Dropbox, and then reopen it. That seems like a bug that can be fixed in short order with Web apps.

Adding Office viewing and editing features is a big plus for Dropbox subscribers, and opening the Office platform to Dropbox files could open up a new wave of prospective subscribers from the ranks of Dropbox diehards.