Extension could not be loaded because it was not properly signed

When starting Photoshop, you get the following error:

The <extension name> extension could not be loaded because it was not properly signed.

Photoshop Error message

This error message means that the installed Extension files are not 100% identical to the files created by the software developer. This could be a missing file, a changed file, an unexpected file, or a change in the file metadata (date).

This issue is not related to a failure of Photoshop, so reinstalling Photoshop will not help in most cases.

Solution 1: Install the latest version of Photoshop

Make sure Photoshop is up-to-date and you are using the latest version.

The current version of Photoshop blacklists extensions that are known to be bad.

Solution 2: Reinstall extensions

This error is typically caused by one of the following issues:

  1. The file metadata has been altered because the files were unzipped and subsequently placed on a cloud or network drive.
  2. The file metadata is incorrect because the files were unzipped using a 3rd-party unzip tool which does not support signed files. This is very common on Windows where customers are much more likely to install such tools. 3rd-party tools are pretty rare on macOS, but occasionally we've seen them become an issue.
  3. Extension files (typically ones with a JS, JSX, or JSXBIN extension) have been removed and placed in quarantine due to false positive detection by anti-virus software. Removal of any Extensions file is an issue, but unknown JavaScript files are more likely to be viewed with suspicion by default.

The solution is to download the Extension ZIP file directly from the Extension developer's website and:

  1. Unzip the ZIP file on the same drive where you have installed Photoshop
  2. Use the unzip tools built into the operating system. 
    • Windows: You must right-click and use the "Extract All" command built into Windows (if you do not see that option, you may need to uninstall your 3rd-party unzip software to get it back).
    • macOS: You must right-click and select Open With > Archive Utility which is the built-in application for macOS.
  3. If you use anti-virus software, make sure to whitelist any quarantined files.

Solution 3: Uninstall Photoshop and delete folders containing old extensions and extra files

If unsigned or unexpected files are introduced into folders used by extensions, this can break signing. Follow the instructions below to ensure all files are removed and then follow Solution 2 from above to download and reinstall the extension from the developer's website.

  1. After uninstall is complete, if the following folders are still present, manually delete them:  

    Windows

    • C:\Program Files\Adobe\Adobe Photoshop <version number>\
    • C:\Program Files\Common Files\Adobe\Plug-Ins\CC\Generator\

    macOS

    • <Macintosh HD>/Applications/Adobe Photoshop <version number>/
    • <Macintosh HD>/Library/Application Support/Adobe/Plug-ins/CC/Generator/

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