If warning of
    "<file name> is not commonly downloaded
     and could be dangerous
"
is given by the downloading of the file, ....



The browser gives the warning such as follows for the file which was uploaded recently.
In that case, please choose [ Keep ] in defiance of warning.

---- Chrome ----
      "<file name> is not commonly downloaded and could be dangerous"
---- Internet Explorer ----
      "This program is not commonly downloaded and could harm your computer"

     


Even if the file does not have a problem at all, this warning is given.

This warning is given for a file with a little number of the downloading
from the statistics data which a browser collects.

In other words, it becomes targeted for warning for a reason "uploaded recently"
even if a file does not have a problem.