If you are running out of storage space, you have a few options.
First, you can try purging your files. The purge option goes through the "data" directory where nanoHUB stores your simulation results, and discards all of the results that have built up since you started using nanoHUB, or since your last purge. You might not have known that simulation results were being kept on your account. In that case, you won't miss them, and "purge" is an easy way of cleaning up.
The default choice is to purge minimally, which means that the purge operation will delete the oldest simulation results first, and continue deleting newer and newer results, stopping as soon as you are under quota.
Other choices are older than 1 day or older than 7 days or older than 30 days, where you explicitly set the time range of simulation results that you want to purge. You can also choose to purge all, which means that all of your simulation results will be deleted.
If you want to keep some of your simulation results, you should choose the manually browse option and follow the instructions to access your file system via WebDAV. Once you have connected that way, you can move select simulation results from the "data" directory to another location where they won't be affected by the automatic purge. You could also browse through other directories and free up space manually.
Note that you might purge and still be over quota if you haven't done much simulation. In that case, you'll need to browse manually and look for other files that can be deleted.
Second, if you are still over your quota or you prefer to keep your simulation results, you can upgrade your account to nanoHUB Pro. For $75.00 per year, you will receive 100 GB of storage for simulations and data, as well as the ability to run 10 concurrent sessions. It's also a great way to support nanoHUB!