How To Clear Scratch Disk Without Opening Photoshop

An error message on your screen is never ideal. Always when you’re in a hurry to finish a job! Scratch Disk full is a common problem! Let’s get it sorted.

Holding Ctrl + Alt or Cmd + Opt on launch will allow the Scratch Disk destination disk to be changed and thus allowing Photoshop to open. 

Scratch Disks are the behind-the-scenes operators of your machine. They come into play mainly when you’re using heavy-duty apps like Photoshop. Sometimes they get full and stop us from opening Photoshop. Let’s see how we can solve this.

Moving the Scratch Disk Destination

Before we get into how to fix the issue, let’s quickly discuss what a scratch disk is and what it does.

Photoshop needs a lot of memory to run (8GB) recommended. But when’s it’s up and running it’s still using memory for you to do each task, to flick between layers, add filters and make multiple file changes. These changes are all saved as temporary files on a Scratch Disk, which is by default your System / Boot Drive. They are stored so your app can perform quicker and more smoothly.

Within the disk, a certain amount of space has been allocated to your Scratch Disk, and if you’re using Photoshop a lot this can quickly fill up.

If you are getting the error message ‘Could Not Initialize Photoshop because the scratch disks are full’ then you need to empty the disk.

The problem is that you can’t open Photoshop to change the Scratch Disk Preferences. Well, you can!

When you launch Photoshop hold down Ctrl + Alt (Win) or Cmd + Opt (Mac). This will give you the option to change the destination drive.

Select the drive that has the most amount of available space. I recommend you buy an external drive and dedicate it as your scratch disk.

Let’s get a bit Techy for a second!

For the optimum Scratch Disk select a compatible port with the largest bandwidth.

Here’s the breakdown of the bandwidth for the ports:

Thunderbolt = 10GB/sec




You don’t necessarily need to understand this. If you select an external drive and don’t use it for anything else it will work a treat.

Clean Up

If you don’t have an external drive to hand there is another way around the problem but it takes some time.

No one likes getting involved in a cleanup, well I don’t! There’s always something more important to do. But if you’re getting Scratch Disk errors I’m afraid a clean-up is necessary. 

If you open a Finder Window.

Search for .tmp or .pst files. This will locate all your temporary files. Select them all and move to the Trash. Empty trash. 

This should solve your opening problem but we need to look at how you have your Scratch Disk set up. (If you haven’t opted for an external drive.)

Scratch Disk Preferences

Open Photoshop – you should be able to, now that you have deleted the temporary files.

Select Edit – Preferences – File Handling and Clipboard


In the File Save Options, you can disable AutoSave Recovery. To be honest, I wouldn’t completely disable it, but instead, change the time. You may find it’s set to 30 seconds, which is causing masses amounts of .tmp files. 10 minutes is plenty.

You can also change the number of Recent Files to Display to a much lower number.

The default is usually 50 so this can be reduced to 10-15. It’s not usually the case that we would have to go back more than this amount, even though it can be set to 1000!

All of these preferences increase or decrease the amount of memory being used by Photoshop, and the number of temporary files being generated by your Scratch Disk.

What Memory is Being Used

The last point I’ll mention is about overall memory.

How much RAM you have on your machine will determine how well or otherwise your machine will perform. 

You may find that you have too many apps open at once and by closing all but Photoshop this may solve your problem. But that’s not really a solution. I have an article about optimum RAM to run Photoshop if you want to check it out.

The other issue may be that your Cloud App may have become disconnected or full and so everything being saved is now going to your hard drive instead. 

Check that this is not the case. Sometimes when Debit Cards are changed or updated we forget to update our details on online accounts and the CLoud stops working. 

Sometimes it’s the simplest of problems that cause us the most amount of difficulty.

In Conclusion

Scratch Disks being full prevents Photoshop from working. Emptying the Scratch Disk or selecting an alternative destination disk will solve your problem.

Here are some other posts that you might find useful:

Can I run Photoshop on 4GB RAM?

How much RAM do I need for Creative Cloud?

Tara Cunningham

My name is Tara. I am a Graphic Designer for the last 25+ years. Designing everything from Wedding stationery to Magazines. I have been using Adobe products since I was in college and know all the tips and tricks that make life a little easier when completing a project. Hopefully you will find the answer to your question on

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