If you've run out of disk space or are about to please read this for what you can do.
The easiest method is to upgrade your web hosting, but read on if you would like to try free up some space.
What's Using My Space?
In most cases where you have not been uploading files to your website, the reason is that email has collected under your emails account.
Sometimes your website visitor statistics (provided with your web hosting) makes you hit your limit as data for this is recorded and grows month-to-month.
You can view where your disk space is being used via your cPanel. You can access your cPanel via http://yourdomain.com/cpanel (obviously replacing yourdomain.com with your actual website domain). Once there, click "Disk Usage" and you will be shown the folders within your account and how much space they are using.
So what happens if I reach my limit?
When you reach any allocated disk space quota limit, then your hosted email addresses will start bouncing emails back to the sender and/or your website may stop working.
Sadly, a common issue with using web hosting for both a website and email, is that if your website consumes all your disk space then your email start bouncing emails. Or vice-versa, if your email takes up all your disk space it may affect your website.
What Can I Delete?
The '/tmp' folder contains your website statistic files that are viewable from cPanel, for example, AWStats and Webalizer statistics.
Over time these can consume a bit of disk space. Many use Google Analytics anyway, so if you do not care much for your web hosting statistics then delete everything in your '/tmp' folder (being careful not to delete anything outside!).
Optionally, you could choose to only keep AWStats by deleting everything in the 'tmp' folder except '/tmp/awstats'. This will often free up lots of space.
Stop Email Building Up
Solution 1: Migrate to Cloud Email
It becoming more common for people to separate the two services. That is, to use web hosting for their websites, and then depend upon Cloud email service such as Google Apps / Mail for their email.
Having your email working with a Cloud solution means it can be accessed at any time and any place with an Internet connection. You'll always have a copy of your email even if your computer crashes or laptop gets stolen. You're also no longer locked into accessing your email via one computer.
If interested, we can help set you up with a Cloud-based email solution for a small price.
Solution 2: Download Your Email
Though many are migrating to cloud-based email, many still access their email via software installed on their computer like Outlook.
To have email software on your computer work, you need to set it up with your email account login and details.
Unless you are absolutely sure what you are doing, when configuring your email account you should always download your email via POP3.
There is also a setting to leave your email on the server after downloading. It is normally set to off by default which is what you want to avoid email consuming disk space. If you download your email and remove from server then you should never run into issue with email consuming all your allocated disk space.