An Apply update dry-run detected x permission issues error, where x is the number of files and directories that the update process could not overwrite, may occur in the Auto Update window in WHMCS:

The contents of the error message can help you identify and resolve the underlying causes of this error.

The automatic update tool is a feature that downloads, extracts, and copies the new files, overwriting the existing files. It performs a dry run test (a test that mitigates the effects of a possible failure) to check the file permissions of all existing files before attempting the overwrite operation.

The dry run simulates overwriting the file without making any file changes. If it encounters a permission problem that could cause the update process to fail, the update process stops before making any changes.

In this case, an error message displays with the details of the file permission issues.

Under the Apply update dry-run detected x permission issues error, where x is the number of files and directories that the process could not overwrite, the system displays the full paths of each file. 

For example:

• /var/www/html/whmcs/configuration.php.new 
• /var/www/html/whmcs/vendor/whmcs/whmcs-foundation/lib/Module

To resolve this error, update the permissions and ownership of the itemised files and directories to allow PHP scripts on your server configuration to write to them, or ask your system administrator or hosting provider.

For more information on making these changes, see:

• Automatic Updater
• How to Assign Permissions to Files and Folders in cPanel
• Changing File and Directory Access Permissions in Plesk File Manager

After you have updated the permissions and ownership, you can start the update process again by navigating to Utilities > Update WHMCS and clicking Update Now.