The majority of these problems are server configuration. Many hosts will not allow you to adjust the settings that affect this unfortunately. However, listed below are the things that we are aware of that can affect uploads and downloads. Here are a some things you can check.
For upload problems:
- Check permissions on your upload directory. Make sure that the server has the permission to read and write to the directory. If you don't know anything about permissions, consult your host for more information.
- upload_max_filesize - default PHP install is set to 2M. This means you can only upload a max file size of 2MB. This setting is usually changed in the php.ini file on your server. Consult your host for more information on changing this value.
- max_execution_time - default setting is 30 seconds. This sets the number of seconds a script is allowed to run. In other words, if it takes more than 30 seconds to upload your file this can cause a time out.
- max_input_time - default is 60 seconds. This sets the maximum time in seconds a script is allowed to parse input data, like POST, GET and file uploads.
- post_max_size - The post_max_size sets the upper limit on the amount of data that a script can accept in this manner. Ideally this value should be larger than the value that you set for upload_max_filesize.
For download problems:
- Permissions - There are often many security settings and file permissions associated in these problems. We could not possibly list them here. Make sure your files are readable and writable by the server. Beyond that, consulting with your host after exhausting your resources is advised.
- As crazy as this may sound, Anti-virus and Firewall software have been known to cause issues. As you download a file and it is filtered or scanned by these software, things can happen that may turn a download into a corrupt file. Disable any software of this type to test if it is a problem for you.