Tech Q&A: If PC files store slowly, it may be a signal of larger problem

Question: My four-year-old Windows 10 laptop has a weird problem when saving Microsoft Word files.

In the past couple of months, the time it takes Word to save a file has gone from nearly instantaneous to taking 10 to 15 seconds. This doesn’t happen the first time I save a new file, just on subsequent “saves.” These are simple, text-only files. What’s wrong? — Ken Burrows, Colorado Springs, Colo.

Answer: I think your hard disk is congested. Either the drive’s contents are fragmented (segments of files are spread around the disk) or the drive is nearly full. As a result, there is less available storage space, and it takes the PC longer to find a spot on the disk to save the file.

Why is there a difference between how the PC stores a Word file initially and how it stores the file after that? To understand, you need to know a bit about how disk drives work.

When a hard drive stores a file, it doesn’t erase the previous version. Instead, it searches for unused disk space where it can store the updated file. This accumulation of new and previous file versions is one reason that your hard drive fills up over time. (The hard drive will eventually overwrite old, outdated files, but not until it runs out of unused disk space.)

As your hard disk fills up, there are consequences. First, the drive might become fragmented. That means that the disk is so crowded that the only unused storage space is scattered at different locations around the disk. As a result, the PC often has to break up files and store pieces of them at different disk locations, causing your PC to store files more slowly. As the drive gets closer to being full, it takes even longer to store a file.

What’s the significance of all this? When you initially store a file, the PC doesn’t have to do much. It finds some unused areas on the disk and puts the file there.

But the second time you store the file, the PC must go to the “Master File Table,” a list of all computer files and their physical locations on the disk, mark the previous version of your file outdated, then search for additional unused disk space to store the latest version of the file. If the disk is congested, the updated file must be divided into chunks and stored at several unused spots on the disk. As a result, your second file “save” takes longer than the first.

The way to fix disk congestion (and shorten “save” times) is to reorganize your hard drive. In the search window on the taskbar, type in “defrag,” and in the resulting menu choose “Defragment and optimize drives.” Highlight the “C” drive (the hard drive) and below that click “optimize.”

During defragmenting, large blocks of data are moved around the disk. The goal is to have entire files stored in one physical disk location instead of multiple locations, so that your PC can store and retrieve files more quickly. The defragmentation process could take a few minutes to a few hours, depending on the hard drive’s storage capacity and how fragmented its contents are. You can continue to use the PC while the process is going on.

There’s also another benefit of defragmenting: Some unwanted data — previous versions of files or deleted files — will be overwritten when all the disk’s data is moved around. That reduces the number of old, unwanted files on the hard disk, creating a bit more unused space. To get rid of more unneeded files, get a disk cleaning program (see

After defragmenting the hard disk, check to see how full the disk is. In File Explorer, highlight the “C” drive. Then right-click the drive, and in the next menu choose “properties.” Compare the disk’s “used space” to its “free space. If the C drive is in the range of 80 percent full, it’s time to move some data or programs to an external hard drive.