I'm experiencing a file corruption error message. How do I correct this?

If an error message is displayed when visiting a WHMCS installation stating that a file is corrupted, it indicates that the file has been modified in some way. Below are some examples of such errors:

The file /path/to/whmcs/includes/clientfunctions.php is corrupted.

The file /path/to/whmcs/includes/invoicefunctions.php is corrupted.

The file /path/to/whmcs/includes/gatewayfunctions.php is corrupted.

The file /path/to/whmcs/includes/ticketfunctions.php is corrupted.

The file /path/to/whmcs/includes/TwoFactorAuthentication.php is corrupted.


The majority of the WHMCS PHP files are encoded using a system called Ioncube which hides the software's source code and prevents them from being modified directly. If these files are edited in any way, they cannot be decoded by your server back into the original PHP code, so are considerred corrupted and an error message displayed.

To resolve this file corruption error:
  1. Download a fresh copy of the WHMCS full release files from http://download.whmcs.com or from your licence reseller
  2. Extract the files(s) which are showing the corrupted error message.
  3. Upload file files to your server, overwriting the existing file.

Should the problem occurr again even after uploading a fresh copy of a file; compare the corrupted file on your server against the file downloaded from our website. Look for any differences between the files, then contact your server administrator or hosting provider to investigate why the file(s) were changed after being uploaded.
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