When you try to crop an image in Photoshop and enter width, height, and resolution values in the crop options, you receive the error that the scratch disk is full and are unable to crop the image.
If you leave the crop options blank, you can crop the image successfully.
Do one of the following:
Solution 1: Specify measurement units when cropping.
Enter the desired measurement units in the width and height crop options. For example, enter 100px for pixels, or 1in for inches.
Solution 2: Set the default measurement units.
To set the default measurement units:
1. Choose Edit > Preferences > Units & Rulers (Windows) or Photoshop > Preferences > Units & Rulers (Mac OS).
2. Select a measurement unit for Type under the Units section of the Preferences dialog box. For example, select Pixels.
3. Click OK.
The error, "Scratch disk is full", occurs when the resulting file is too large for the scratch disk to process. This error can occur if a file was created in pixel dimensions but the crop options are entered in inches (the default measurement unit). For example entering 700 x 800 in the width and height crop options will default to inches, instead of pixels. You need to specify 700px x 800px to achieve the desired result or specify pixels as the default measurement unit in the Preferences. If you leave the crop options blank, then Photoshop will crop the image to the specified area using the same measurement units in which the image was created.