A "Failed to write to disk" error in WordPress is usually caused by one of the following:
- The hard drive of the server your account is on is full
- The tmp (temporary folder) of the server your account is on is full
- The permissions on the folder being written to are set incorrectly.
The most common of the above issues is the tmp folder being full. Unless you have modified the upload_tmp_dir setting in your php.ini file, the default folder WordPress uses is the tmp folder of the server, which should not usually pose any issues. Since this is a folder customers do not have access to, you will want to contact our Support Department regarding this error.
If you want to check where the upload_tmp_dir is pointed to, you can upload a phpinfo.php file to your account and check the value for "upload_tmp_dir" for the following:
- "no value" means WordPress is using the default tmp folder of the server as noted above. Please contact technical support for further assistance
- Anything other than "no value" would point to a different folder. This should be a folder in your account which you have control over. You will want to make sure the permissions on the folder are set to 755.
A note to visitors who are not currently customers of Web Hosting Hub: This is usually an error that needs to be brought to the attention of your web hosting company so they can check the server's tmp folder for you. You can check to verify what folder the "upload_tmp_dir" is pointed to as described above. If it's the default folder, contact your host to check into resolving the issue with the tmp folder of the server. If it's not the default folder, check the file permissions on that folder using either your hosts version of File Manager or an FTP program.