The College of Engineering provides file-level 'snapshots' of your network storage (including your home directory, research shares, or admin shares). Restoring a snapshot of a file is kind of like retrieving a file from the Recycle Bin - it involves locating a read-only copy of an older version of a file or directory and copying it back into its original location.
First, open File Explorer (or My Computer), and right-click the drive or share that contains your file. Select 'Restore previous versions'.
The dialog box that appears should show several snapshots of your data at different points in time. Select the most recent one that contains a correct copy of your file. Note that you are not actually restoring any data at this point; you're just looking back at a read-only copy of the data at a point in history. So if you're sharing a drive with several other people, there's no need to worry about overwriting their files at this point. After selecting a previous version, click 'Open'.
A new window will open with the read-only historical copy of your share. Note the time shown in the address bar, and the difference in the modified time on this version of my important Excel file, below (the current file, from the previous screenshots, was modified at 2:05 PM):
At this point, there are several ways to copy the file back into its original location. You can drag-and-drop the file, for instance, or you could right-click it to 'copy' it, shown below, and then 'paste' it back into place.
And that's it! Note that snapshots are usually only available for the last few weeks. You can find specific information about the snapshot schedule in the FAQ 'What kind of backups are available on the College's network storage?'.