Hello,
Make sure you have the Level of "Download Insight" at 5 Typical.
Download Insight determines that a downloaded file might be a risk based on evidence about the file's reputation. Symantec collects information about files to determine their reputation and makes the information available to Download Insight. The slider indicates a range of reputations, from most likely to be malicious to least likely to be malicious.
You can adjust the slider to change the reputation level at which files are considered malicious or unproven.
When you set the sensitivity level higher, Download Insight detects more files as malicious and considers fewer files as unproven. At higher levels, Download Insight returns more false positive detections. Only the files with the best reputations are allowed.
At lower sensitivity levels, Download Insight detects fewer files as malicious and returns fewer false positive detections. However, more files are considered unproven.
Note: Move the slider to view a description of each level. Each description provides information about how the level allows or blocks files and its potential false positive rate.