If you download lots of apps, movies and TV shows, and music, an Android smartphone with a memory card slot is a great way to save money. Instead of paying hundreds of dollars for added built-in storage, you simply spend about $20 on a 64GB microSD card.

But phones with an old operating system often fail to recognize that extra storage capacity. If you've ever received the dreaded "Insufficient Storage Available" message when trying to save a photo or update an app, you're familiar with this issue.

This annoying problem has been fixed on smartphones that run Android 6.0 (Marshmallow). But for the vast majority of Android phones, data is stored in the device's internal memory by default. Here's what you need to know to fix the issue.

Application Management

To move some apps to a memory card, open the Settings menu by pulling down the notifications bar at the top of your screen and hitting the little cog-like icon on the upper left.

Now tap the Application manager, which lists the apps on your phone. (Typically, the default view shows them all, but the roster might be filtered to include only those that are running or disabled, etc.)

When you open an app on the list, you should see a Move to SD button at the bottom of the screen. Push it. That will trigger the phone to move that app and/or the data files associated with it from internal memory to the microSD card. Once the task is completed, the button will change, allowing you to move everything back to the phone if you choose.

As you go through the process, you’ll notice that many apps cannot be moved. That’s okay, because app files are generally small—several hundred kilobytes or maybe a few megabytes. But the data files that are linked to them, particularly multimedia files, do migrate, and those can be much larger.

Case in point: The Vudu movie-playing app on my LG G3 takes up just 37MB of storage, but the copy of “Ant-Man” I downloaded with it gobbled up more than 800MB of storage. 

An Android smartphone Insufficient Storage Available warning
One way to avoid the insufficient storage available warning (left) is to shift file saves to an SD card via the Application Manager in Settings.

Moving Photos, Videos, and Other Files

With their high-megapixel image sensors, smartphone cameras might be the biggest data hogs of all. A still photo can easily exceed 5MB of storage space, while an eight-minute HD video can consume a full gigabyte or more. At that rate, one long family reunion and you're on your way to an insufficient storage available warning.

If you insert a new memory card while you have the Camera app open, you often see an on-screen pop-up asking whether you want to save your photos to the SD card. But, barring that, you can manage your storage options with ease in the camera’s on-screen settings. However, once you've shot a photo or video, you can't move it from one location to another with that method.

That's when you need to use Android's File Manager app (called My Files on Samsung smartphones). It works pretty much like the File Manager on a desktop computer. In fact, you can use it to move PDFs, text docs, spreadsheets, and other large documents, too.

On-screen pop-ups (left) let you save photos to a new memory card. You can also use File Manager (right) to move them out of internal storage.

To find the app, type "File" in your phone's search tool. (On LG phones, it's sometimes housed in a desktop folder called Tools.)

Open the app and tap the All Files submenu. You’ll see two folders: Internal Storage and SD card. If you're trying to move photos and videos, open Internal Storage and look for the DCIM folder.

Inside that folder, open Camera. Presto! You should see a thumbnail list of all the photos and videos in your phone's internal storage. At the very bottom of the screen, look for a copy button, often designated by a symbol that resembles two overlapping pages.

Once you press that button, the photo list will include check boxes. Select all the items you want to move to the SD card and press Copy at the bottom of the page. It may take several minutes, but the app will begin to move those files to the SD card.

To hunt down your PDFs, text files, and more, you might need to search the other directories in Internal Memory. For instance, the Download folder might contain all those e-mail attachments you’ve saved over the years. And apps like Periscope sometimes have their own photo stash. Once you've located the files, follow the same procedure outlined above for photos.

After you've shifted the apps, photos, videos, and other files to the SD card, you should find that your phone's memory problems are cured. For more information on cell phones and services, be sure to check out our buying guide.

Check out the top smartphone cameras in our reviews and the smartphones with the best battery life. And check out our reviews of phone plans and carriers.