If you're using network shared folders in Windows then you may run into what I can only describe as a bug in Windows that only occurs in specific scenarios. If you try copy and pasting a file from one network share to another using the same Explorer window then it will work fine, but if you open two windows to the shame shared folders and then try and copy a file from one to the other (regardless of what sort of file it is) you will be greeted by the message "Windows Security: These files might be harmful to your computer. Your internet security settings suggest that one or more files may be harmful. Do you wish to use it anyway?" as seen below:



Of course this message makes little sense when copying MP3 files, AVI files, JPEGs or other mundane multimedia, not to mention Windows seems to think that this is an Internet server for some reason and not another machine on your own network. So disabling this makes sense otherwise those messages will get tiring very quickly.

Oddly enough to fix this we need to go into Internet Explorer and alter your Intranet Security Settings. Unfortunately there is no way of turning this message off globally, but you can at least disable it for specific machines. The procedure is as follows.

First, open up Internet Explorer and then go to Tools on the toolbar and select Internet Options. This will then open up the Options window. From here you now need to click the Security tab, select Local intranet and then click Sites.



Now ensure that Automatically detect intranet network is ticked (it is by default) and then click Advanced.



You should now be faced with the window in which to enter the exceptions to the annoying warning message. Enter the IP address of the machine that contains your shared files and click Add.



And that's it. No more annoying warning messages when you try and copy files from one window to another. Hopefully Microsoft will fix this with an update at some point in the future, but for now this helps avoid the bug.