Graphical Interface

UltraDefrag GUI is pretty straightforward: you select disks and then either analyze, or defragment, or optimize them. If multiple disks are selected they will be processed one by one. After the job completion you may open a file fragmentation report to check which files are still fragmented and why.

If you see locked files in the report it does make sense to perform a boot time defragmentation. Click Action > Boot time defragmentation and select the action you would like to perform. The program will show a reboot confirmation dialog then. Click Reboot now to reboot the computer and start the boot time processing immediately or click Reboot later to process selected disks at the next system reboot. Some files cannot be defragmented even at boot time, but most of them can.

To defragment disks automatically click Settings > Preferences, then open the Automatic defragmentation tab, select the disks and click OK. The program will defragment the selected disks from time to time automatically when the computer is idle.

There is no need to keep UltraDefrag GUI open for the automatic defragmentation to run as the job gets done using a special scheduled task.

If the program says some of your disks need to be repaired, select them and click Action > Repair drives.

Drives list

The top part of the window displays a list of disks available for defragmentation. By default the program skips removable ones (USB sticks and memory cards). Click Action > Skip removable media to set whether they have to be included to the list or not. To refresh the list click Action > Rescan drives.

For each disk the program shows the following information: the disk label (if it exists), the disk processing status, the fragmentation level, the total capacity and the amount of free space available on the disk.

The program calculates the fragmentation level using the following formula:

fragmentation level = number of fragments requiring defragmentation / total number of fragments

Cluster map

The bottom part of the window shows the cluster map of the selected disk. It represents disk clusters by little colored squares. The top left square represents the first cluster, the bottom right - the last one. All the clusters in between are organized by rows. The colors have the following meaning:

Not fragmented
Locked (system)
Free space
Unused map cell

Initially the program draws a green map, because it has no information about files and free space gaps on the disk. Then, it finds out where the free space is located and shows it on the map. And, finally, the program collects information about all the files on the disk and updates the map respectively. If a file has to be skipped in defragmentation because it's bigger than specified in preferences the program uses a darker color for it, otherwise it uses a lighter color. The master file table gets drawn using the dark magenta color, the space reserved for its expansion - using the light magenta color. The map cells which are not in use get painted gray.

Each map cell represents an integer number of clusters. So, for instance, if a disk has 100 clusters, but the map contains a bit more cells those redundand cells will be not used at all. On the other hand, if the map contains exactly 200 cells they will be all in use, reflecting 2 clusters each.

For the free space the program uses white color by default, but it can be easily changed. Just click Settings > Preferences, then open the Miscellaneous tab and choose another color there. Also you can set the grid color, the map block size and the grid line width there.



Analyze (F5; Enter)
Analyze the selected disks.
Defragment (F6)
Defragment the selected disks.
Quick optimization (F7)
Perform quick optimization of the selected disks.
Full optimization (Ctrl+F7)
Perform full optimization of the selected disks.
Optimize MFT (Shift+F7)
Optimize the master file tables on the selected disks.
Pause (Space)
Pause or resume the job. The current file operation will be completed to avoid data corruption.
Stop (Ctrl+C)
Abort the job. The current file operation will be completed to avoid data corruption.
Boot time defragmentation
Start the boot time defragmentation (disabled in portable edition).
Show report (F8)
Open the file fragmentation report for the selected disks.
Skip removable media (Ctrl+M)
Exclude removable disks from the list.
Rescan drives (Ctrl+D)
Update the list of drives.
Repair drives
Repair the selected disks.
When done
Set the action to be performed after the job completion. The default is None, available actions are: Exit, Standby, Hibernate, Logoff, Reboot and Shutdown.
To shut the computer down successfully both your system and hardware configuration must support shutdown and power off, otherwise Windows might either reboot the computer or simply stay running. The same way neither standby nor hibernation will work when they are not supported by the hardware or are disabled in Windows.
Exit (Alt+F4)
Close UltraDefrag.


Preferences (F10)
Open the preferences dialog.


Contents (F1)
Open this handbook.
Best practice (F2)
Open the Tips and Tricks chapter of this handbook.
Frequently asked questions (F3)
Open the Frequently Asked Questions chapter of this handbook.
Cluster map legend
Show the Cluster map section of this chapter.
Get access to debugging information:
  • Open log (Alt+L) opens a log file with debugging information if one is enabled.
  • Send bug report opens the Troubleshooting chapter of this handbook.
About (F4)
Show general information about the program.



On the general preferences tab you can select your language and set whether the program should check for available updates at startup or not.


On the defragmentation preferences tab you can select which files to defragment and which files to skip. Also it is possible to skip individual fragments.

It does make sense to skip temporary files as well as big files and fragments. For instance, when you watch a movie Windows spends just a few milliseconds to advance from one fragment to another, but the overall watching time is about 2 hours. So, you'll never gain any performance improvement if you will defragment movies. And the same is true for all the other multimedia files.

Also it does make sense to skip archives. Usually they serve for backup purposes and never get accessed otherwise. So, in most cases you'll see no performance improvement if you will defragment them.


On the optimization preferences tab you can set the file sorting criteria and order. Also you can exclude big files from the optimization process, which does make sense as sorting of big files does not improve system performace in most cases.

By default the program sorts files by path in ascending order and skips all files bigger than 20 MB.

Automatic defragmentation

On the automatic defragmentation preferences tab you can set the disks to be processed automatically and access the schedule. Also you can disable the automatic defragmentation completely or set a custom script for it.

Automatic defragmentation preferences are not available in the portable edition of UltraDefrag.


On the miscellaneous preferences tab you can exclude disks having a certain fragmentation level, adjust cluster map options and set whether the program has to be minimized to the system tray or not.


On the advanced preferences tab you can enable advanced features and access the main configuration file.

Check Deep action if you would like to process all files on the disk ignoring all the options set on the defragmentation and optimization tabs. Usually that does not make sense, but in some cases it is useful. For instance, if you would like to move everything to the beginning of the disk and pack as tight as possible to prepare the disk for shrinking, just check this option and perform the full optimization then.

If you would like to quickly test disk processing methods check Quick test mode. No files will be actually moved on the disk, but everything else will work the same way as in normal operation.