Take a look at the file in the explorer. Windows Defender may think the file is unsafe and blocks the complete download. Other virus software may quarantine files. Try running the program as administrator. If that doesn't work, try this only if you have a record of the keys. There may be something in the original installation blocking the new version. Uninstall ARC500 from your computer. Try the new version again. Make sure you don't have ARC500 (Basic) and ARC500 Pro confused.