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Troubleshooting

Fix "Not a Valid Photoshop Document" Error in Bulk Mockup

Overview

If you see the error "Could not open because it is not a valid Photoshop document" when running Bulk Mockup, temporary files in your folders are likely the cause. Mac systems generate hidden temporary files (starting with a dot) that interfere with Bulk Mockup's file processing. This tutorial shows you how to identify and remove these files to resolve the error.

Step 1: Configure Bulk Mockup

Open the Bulk Mockup panel in Photoshop and configure your folders:

  • PSD Template Folder - Select the folder containing your mockup templates with smart objects

  • Design Location - Choose the folder with your design images (PNG/JPG files)

  • Export Location - Set where you want the final mockups saved

Click Run Bulk Mockup to start processing.

Screenshot of the Bulk Mockup Photoshop plugin interface on Windows, showing fields for PSD Template Folder, Export Location, Design Location, Design Resize Options (with JPEG file type and aspect ratio set to Yes), and Run Bulk Mockup button. Photoshop Layers panel visible in background.

Step 2: Identify the Error

If temporary files exist in your folders, Photoshop will display an error message during processing:

Close-up of Adobe Photoshop error dialog in Bulk Mockup workflow stating 'Could not open '._t-shirt mockup-vacation-edition-v03.psd' because it is not a valid Photoshop document.' Plugin UI partially visible with Run Bulk Mockup button.

The error message often shows a filename starting with "._" followed by your actual file name. This indicates a Mac-generated temporary file is blocking the process.

Step 3: Locate Temporary Files in Template Folder

Navigate to your PSD Template Folder and look for files with these characteristics:

  • Filename starts with a dot (e.g., ._filename.psd)

  • File size is approximately 4KB

  • These files may be hidden by default on Mac systems

Windows Explorer view of 'Mockup Template' folder showing four PSD files, including two small 4KB files with preceding dot (e.g., ._ filenames), indicating temporary Mac-generated files. Bulk Mockup plugin visible in Photoshop background.

On Mac, press Cmd + Shift + . (period) in Finder to show hidden files and locate these temporary files more easily.

Step 4: Locate Temporary Files in Design Folder

Check your Design Location folder for the same type of temporary files. They will have the same dot-prefix pattern and small 4KB size.

Windows Explorer view of 'Designs' folder containing four image files (PNG/JPG), including two 4KB temporary files starting with dot (._Artwork, ._Untitled-1). Navigation pane shows path to Downloads > Archive > Designs.

Step 5: Delete Temporary Files

Select all temporary files (those starting with a dot and sized at 4KB) in both your template and design folders, then delete them:

  1. Select the temporary files with dot-prefixed names

  2. Press Delete or move them to Trash

  3. Confirm the deletion if prompted

These temporary files contain no actual data, so deleting them is safe and won't affect your mockup templates or design files.

Step 6: Re-run Bulk Mockup

Return to Photoshop and run Bulk Mockup again:

  1. Verify your folder settings are still correct

  2. Click Run Bulk Mockup

  3. Processing should now complete without errors

Adobe Photoshop Progress dialog showing 'Reading Photoshop format' with green progress bar during Bulk Mockup processing, indicating successful file handling post-deletion of temp files. Bulk Mockup panel and toolbar visible.

Step 7: View Your Results

Once processing completes successfully, check your Export Location folder. You'll find subfolders (named after your design files) containing the generated mockups.

Windows Explorer view of 'Export/Artwork' folder containing generated T-shirt mockup image '08-tshirt-mockup-vacation-edition-v03-Artwork' thumbnail, with Photoshop interface open to PSD file on left. Additional frame at 02:20 shows 'Untitled-1' variant.

Each design file will have been processed with each template, creating individual mockup files ready for use.

This issue occurs specifically on Mac systems. If you transfer files from Mac to Windows, temporary files may carry over and cause the same error on Windows machines.

For more information on using Bulk Mockup effectively:

Need More Help?

If you have questions about this error or encounter any issues, contact the Bulk Mockup support team at [email protected].

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