I just downloaded the installer, but upon opening the executable I got the error: “Windows cannot access hydromagic_full_64bit.exe”.

This is probably a problem with access privileges or a corrupted download. Please check the following:

1. Check whether the download has been completed, this message might occur when the browser has been closed before the file was downloaded completely.
2. The file might be removed by a virus scanner when it detected is as a virus (false positive);
3. When installing the file from an USB stick it might be blocked, copy the file to your local harddrive first;
4. The download was corrupted, please delete the old file before retrying the download;
5. 5. The system administrator blocked the execution of downloaded files on your computer.