What to do when you need to clear your scratch disk

History of digital photography has seen a paradigm shift, all the thanks to Photoshop. Nowadays, when you observe an image or picture, there is a high chance that the image has been photoshopped.

Photoshop, a one-stop solution to all the image editors, offers excellent features and tools, gives it an extra nudge to reach the level of premium quality software that it now provides.


Photoshop is a very robust and important software. Nowadays, its capabilities can be expanded by installing its plugins! It is used in raster graphics editing as well as in digital art.

Is Photoshop perfect? Errors and glitches do exist. Scratch Disk is the most common area for the error to occur. But before discussing the errors, let’s discuss what a scratch disk is


Photoshop was developed by the tech giant, Adobe Inc. in 1988 for Windows and Mac OS. It was developed (coded) by the programmers Thomas and John Knoll. Photoshop has become so popular that its name is often used as a verb!


The earlier versions of Photoshop (starting from 1988 onwards) had the suffix CS followed by a number. Example: Photoshop CS 5. With the development of the Creative Cloud platform by Adobe Inc. in 2013, the suffix from then on changed to CC followed by the year of release. Example: Photoshop CC 2019.

A wide variety of people use Photoshop. College students use it to design posters for important college events. Graphics designers use it for a wide range of purposes. Organizations use it to create posters to advertise important events. The photo editors in photo studios use it to refine photographs of people. The list goes on. 

It is therefore essential for people who use Photoshop to keep it in smooth running condition. One of the key reasons why Photoshop won’t function properly at times is its cache stored in its scratch disk. It can cause Photoshop to function very slowly at times or can even cause Photoshop not to launch at all.


Before moving to the crux of the article, we will explain as to what exactly Scratch Disk is. A scratch disk acts as a hard drive while using programs like Photoshop or Final Cut Pro. These programs require a certain amount of storage when the RAM on your system is not sufficient enough to carry out an operation. Photoshop or Final Cut Pro work fine when the workload of the scratch disk is divided.

Usually, Scratch Disk appears when you play a lot with large images and programs like Photoshop, which covertly consumes your system’s space by creating a pile of project temp files.

Photoshop also allows us to set other disks (or portions of disks) as scratch memory when the hard drive is full. In this article, we talk about how to clear the scratch disk when it’s full-on Mac OS as well as on Windows 10 OS and how to clear the scratch disk on these operating systems without opening Photoshop. 


how to fix photoshop scratch disk full error

The problem with Photoshop is that it does not always get rid of temporary files when they are no longer needed. These temporary files can get accumulated in the primary scratch memory and users sometimes get “scratch disk full” error. We shall have a look at how to clear scratch disk in Mac O.S.:

So, how difficult it is to clear scratch disk? Fret not; these following measures will help you in resolving the issue:

  1. Open any of your works in Photoshop.
  2. Then click the Edit option in the Menu bar.
  3. Hover your mouse over the Purge sub-menu.
  4. You will see four different options which are Undo, Clipboard, Histories, and All.
  5. If any of these options are greyed out, it means that they have already been deleted. 
  6. Select the specific option you want to delete or choose the ‘All’ option if you want to delete all of your caches. 
  7. A message (warning) box will pop up if you select any of the four options. It will say that ‘purge’ action done on caches cannot be undone. So kindly ensure that you don’t need any previous versions of your works/projects before clicking O.K. option (confirmation). 
  8. Tada! You have successfully cleared your scratch disk in Mac OS.

Sometimes these temporary files (a.k.a. caches) can be stored in other parts of your computer’s memory apart from the four options mentioned above. Finding out where they have been saved and then deleting them can be a tedious task. It is for this reason that a company called MacPaw developed software called CleanMyMacX to search for and remove these temporary files (caches) automatically. Here is how you use the CleanMyMacX software:

  1. Launch CleanMyMacX software.
  2. The first option on the top left corner (menu bar) will be System Junk
  3. Select that option and then make sure you check the box labeled System Cache Files along with other checkbox options if you want to.
  4. Then click on the Clean button at the bottom middle. 
  5. All your computer’s cache would have been found and deleted permanently by this software.

How to Clear your Scratch Disk in Windows 10 OS?

If you have installed Photoshop on a Windows 10 OS, the same procedure to clear its cache applies as in Mac OS. That is, you have to go to the ‘Edit’ option in the menu bar, hover your mouse over ‘Purge’ sub-menu and select an option from the four options that will appear. 

However, in Windows 10 OS (or any Windows OS for that matter), sometimes you will get the “Scratch memory full” error even when there is some free memory space left in the scratch disk (by default it is the hard disk in C drive). This is because Photoshop, operating on a Windows platform, needs its cache to be stored in sequential memory locations for it to use the cache effectively and delete it afterward. 

Over time, Photoshop’s cache along with the system’s cache, gets fragmented and stored in different, non-sequential memory locations. Hence, Photoshop runs more slowly (it’s not able to utilize its cache effectively), and its cache files get accumulated in the scratch disk, wasting precious memory space and eventually causing the scratch disk to become full. 

In order to keep Photoshop running efficiently on a Windows 10 platform, one needs to find which disks/drives have been allocated as its scratch disks and then defragment them. By default, it is the C drive (only one scratch disk) but this is how you can find out:

  1. Click on the Photoshop option in the menu bar.
  2. Then click on the Preferences sub-menu option.
  3. Then click on Performance option.
  4. A window titled Preferences will pop up.
  5. At the bottom left, you will find the heading, Scratch Disks, which shows which drive/s Photoshop is using as its scratch disk/s. 
  6. You can then defragment that drive/s to keep Photoshop running smoothly on your Windows 10 OS. 

How to Defragment your drive in Windows 10?

Once you know which drive/s Photoshop uses as its scrap memory, you can defragment the same by:

  1. Going to Control Panel via the search bar or by pressing the Windows button and ‘R’ simultaneously and typing Control Panel in the Run text box. 
  2. Once inside the Control Panel, you should click on the System and Security option. 
  3. Then you should click on the Administrative Tools option. 
  4. Then you should double click on Defragment and Optimize drives option.
  5. Choose the drive/s the scrap disk/s is/are in and then click on the Analyze button first.

Once the Analysis is complete, click on the Optimize button. Your drive/s will be defragmented and Photoshop will run smoothly on your Windows 10 OS.

Also Read, Virus Cleaner( Hi Security )- The Best antivirus app in Play Store ( Full Review)

You always have the option to delete your old files and make some free space

How to clear Photoshop’s cache without opening Photoshop? (for both Windows 10 and Mac OS)

In Photoshop’s older versions, its temporary files’ names start with pst followed by a series of numbers and end with the extension, .tmp. You can type pst%.tmp in the search bar of Windows 10 or Mac O.S. and find all of Photoshop’s cache. Once you find them, close Photoshop if it’s open and then delete the cache to free up memory space in your scratch memory.

Photoshop will now run smoothly. In the more recent versions of Photoshop, its temporary files start with the name Photoshop Temp followed by a series of numbers. Type ‘Photoshop Temp’ in the search bar of Windows 10 or Mac OS and you’ll be shown all of Photoshop’s cache. Close Photoshop if it’s open and delete all of its cache (temporary files) to free up your scratch memory. Photoshop will now run smoothly on Windows 10 or Mac O.S.  


If the occupied space on your system hard disk crosses over the threshold limit of 85%, it starts to slow down. Perhaps, changing the scratch disk can resolve this problem with ease. Unlike other options, where you have to worry about your old data.

If you don’t have another hard disk, you can easily purchase one on online e-commerce sites or nearby electronic store. SSD is considered as the best option for Mac OS Scratch disk.

Follow these simple steps to change your scratch disk:

  1. Click on the Photoshop menu
  2. Now go to Scratch Disk, under Preferences
  3. Tick the checkbox to which you want to assign as resign as a Scratch Disk
  4. At the top right corner, click OK.

(Note: It is recommended to restart Photoshop after making this change for better performance)

If you find any difficulty in opening the Photoshop software, then the culprit could be the insufficient space left on the drive. Changing your Scratch disk can help in this situation. But you cannot use the above-mentioned steps, as it needs Photoshop to run. 

According to Adobe Forum, there is a way to change your Scratch disk, without demanding the Photoshop to run. Here are the steps to change drive:

  1. Start Photoshop (it doesn’t matter if it opens entirely or not)
  2. Hold the ‘CMD’ + ‘OPTION’ as soon as Photoshop starts
  3. A pop-up will appear with Scratch Disk Preference
  4. Select another Scratch Disk (with more space)
  5. Click on OK after choosing your desired drive

(Note: Do not forget to clean the files, that was clogging your hard drive)

Once you are done with the above steps, Photoshop will run effortlessly as it used to. You just have to make sure that the drive you are selecting has more space left than the previous one.

Also Read, Now You Can Record Videos Online On Mac


Resolving ‘Scratch Disk Full’ error on Windows 10 is no different from Mac — clearing Photoshop cache, deleting temporary files, clearing disk space and changing Scratch Disk.

However, there is a slight change in the steps of selecting or removing a drive as a Scratch disk. For windows users, the following are the steps to change the drive:  

  1. Open Photoshop in Windows
  2. Go to Edit tab at the top
  3. Hover over the Preferences option, you will get many options here
  4. Click on Scratch disk, a list of available drives will appear
  5. From the available drive list, you can select one or many drives as your Scratch disk
  6. Once you are done selecting, click OK

Also Read, Here’re the top 5 drawing apps for your iPad


These errors are common, and once you follow the methods mentioned above, you are all set to avoid the warning signal of “Scratch Disk full”. And with the aforementioned tips, get ready to experience a smoother running Photoshop that will make editing more fun.

We are open for questions and feedback, if you have any, write to us in the comments section below.


  • How to reset tools in Photoshop?

In some cases, the tools in Photoshop may crash, and the only way to resolve this issue is to reset the tools. Following steps will help you in resetting the tools:

  1. Control + Click (Mac) or Right-Click (Windows) on the Tool Preset Picker in the tool options bar
  2. Select Reset All Tools to reset all tools to their factory default settings
  • Are there any third-party software available to clean temporary files?

Yes, there are many third-party software available in the market. However, we don’t recommend to use any of those.

  • Can I restore to the previous version of my work after clearing Scratch Disk?

No, once you have cleaned Scratch disk, then there is no way to get back to the previous version of your project. Scratch Disk consists of the previous versions in the form of temporary files, and cleaning it deletes it from the system, making it impossible to recover.

  • Will my current project also get deleted, if I delete temporary files?

No, even if you delete the temporary files, the current project on which you are working will remain in the system. However, the previous versions will get deleted, so you can’t undo the steps you have done.