- automatic-updates: your computer and any other programs you use will often keep working in the background, even if you're not actively using that program, in order to keep your system/program up-to-date. Anti-virus programs will periodically use your internet connection to check back with their malware database for any updates. You should have an option to turn off auto-updates and/or schedule them for a later time.
- multimedia content: Netflix, Hulu, YouTube, Facebook, Tumblr, Instagram, news sites, and other websites will contain videos, animated gifs, and sound clips that may start playing as soon as you land on the site. So much content, so easily available almost everywhere on the internet.
or adjusting your Netflix playback quality to SD: https://help.netflix.com/en/node/87
- more data sources can be found here, as posted by a fellow community member:https://community.myhughesnet.com/hughesnet/topics/data-usage-sources-common-and-not-so-common
The most important tool to download is the Status Meter, available in the Customer Support Center, to help you monitor your data usage: supportcenter.myhughesnet.com
For troubleshooting the matter;
Do You have an anti-virus/anti Malware solution(s) on your computer? Malware can use an enormous amount of data.
If you don't have anti malware, i recommend Malwarebytes.