[Solved] System Hard Disk Drive Needs Optimization but Won’t Defrag

What should you do if you find your system hard disk drive needs optimization but won’t defrag, which is stuck at 29%, 77%, and even 100% when you’re optimizing hard drives. In this post, you will learn three alternative optimization methods to evade this issue.


By Hedy / Updated on May 12, 2023

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System hard disk drive needs optimization (77% fragmented)

"When I open the Defragment and Optimize Drives application after updating Windows from Win 7 to Win 10. The system hard drive stays at 77% fragmented and when analyzed it moves to 100%, then when I optimize it runs a very few seconds and stays at 77% fragmented and says it needs optimization. Photo attached I hope. Computer seems to be slow and freezing."


Your slow disk performance can be caused by fragmentation in the file system. When a hard drive is fragmented, its data blocks are scattered everywhere around the hard disk, so it takes longer to access the required data. That’s why you wish to optimize hard drive performance by defragging disk.

However, when you use Windows utility Defragment and Optimize Drives to defragment hard dives, you may find that it shows system hard disk drive needs optimization but is stuck at 100%, 77%, or 29% fragmented. In other words, the program allows you to optimize drives but has problems defragging the system reserved drive.

Why can't I defragment my system disk?

Why system hard drive needs optimization but can't be defragged? You should figure out what system reserved partition is. It contains boot files like Boot, System Volume Information, bootmgr, BOOTSECT.bak, etc, occupying around 100 MB in Windows 7, 350MB in Windows 8/8.1, and 500MB in Windows 10.

If system reserved partition is on the wrong disk, you can move it to the right drive, and if it's too small, you can increase system reserved partition size. But do you need to optimize system reserved hard disk drive if your PC gets slow? No, files on system disk can be in fixed positions and have nothing to do with disk performance. Thus, you often see the scene of system hard disk drive needs optimization but won't defrag.

If you want to make your disk run faster, you can try the following ways to increase the read and write speed of disk.

Alternative ways to optimize disk when system hard disk drive needs optimization but won't defrag

Based on the comprehensive analysis, a slow or freezing computer appears usually when a lot of files, whether useful or useless, pile up on your hard drive, or when C drive is full as time goes by. To evade the message of system hard disk drive needs optimization 100 fragmented, an all-around third-party tool called AOMEI Partition Assistant Standard is recommended to you.

It's a free disk optimizer for Windows 11/10/8/7/XP/Vista that can efficiently and easily optimize your hard drive by eliminating junk files, moving programs, extending C drive, wiping hard drive, etc. Now, you can get this freeware downloaded on your PC, and see how powerful it is to boost disk performance.

Download FreewareWin 11/10/8.1/8/7/XP
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Way 1. Remove junk files from system drive

Deleting junk files is one of the simplest and most effective ways to free up space on your disks, especially on your C drive.

Step 1. Launch and open AOMEI Partition Assistant Standard, and then click "Free up" > "PC Cleaner".


Step 2. In the pop-up window, click "Start Scan" to scan for junk files on your computer.


Step 3. Wait for a while until the scanning process completes.


Step 4. After the scan is completed, all kinds of available junk files will be listed. Then, tick the junk files you want to clean, then click "Clean All" to begin cleaning.


Step 5. When the cleaning is done, click "Back" to exit.


Way 2. Move programs and files from C drive to another

Another useful way to release more space from C drive is to move files, folders, or programs from C drive to another drive with enough space. After transferring, you can use them normally as before. Please upgrade to AOMEI Partition Assistant Professional edition and follow the steps below.

Download Pro DemoWin 11/10/8.1/8/7/XP
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Step 1. Launch AOMEI Partition Assistant Professional, click "Free up", select the "App Mover".


Step 2. You will see 2 options: move apps or move folders. Here we choose "App Mover".

Tip: If you want to move files or folders to another drive, click "Move folders" in this step.


Step 3. In the new window, you will see all partitions. Select one partition that you want to move applications from and click "Next".


Step 3. Choose applications you want to move and select the target location, then click "Move".


Step 4. In the pop-up window, you'll be reminded of a warning. Read it and click "OK" to begin the program migration.


Way 3. Extend system partition size

If you don't want to change the files location, you have to try enlarging the size of C drive, which has been proven to be the quickest and easiest way to optimize your computer. Only in three clicks, you will get a faster PC with ease.

Step 1. Open AOMEI Partition Assistant Professional and find the drive with enough free space like D drive. Right-click it and choose the button "Allocate Free Space".


Step 2. In the pop-out window, you can choose the size you want to allocate and the destination drive you want to add.


Step 3. If all the operations are right, please click "Apply" > "Proceed" to commit.



That system hard drive needs optimization is usually seen when defragging the hard drive. The reason why system hard disk drive needs optimization but won't defrag is that you don't need to optimize it at all. In this post, you've learned three alternative ways to disk defragment if you meet a slow PC. Try any one of them and you'll find your computer performance has improved.

Hedy · Staff Editor
Hedy is an editor of AOMEI Technology. She is very good at solving problems of partition management, and she wants to share all the problems she had already solved to users who met the same questions.