Google Safe Browsing, which is a service used by Google Chrome and other web browsers, has been known to flag our download pages as "containing harmful programs". The message given may be similar to the one shown below:
The site ahead contains harmful programs
Attackers on autohotkey.com might attempt to trick you into installing programs that harm your browsing experience (for example, by changing your homepage or showing extra ads on sites that you visit).
We do not and never have done what is described above. It is believed that these warning pages may be caused by antivirus false positives or obscure policies set by Google relating to classification of unwanted software.
Discussion and further information about this issue can be found in forum topics such as Google is blocking autohotkey.com.
If you have installed AutoHotkey and wish to remove it, the process is very straight-forward, and there are also detailed instructions.
See the FAQ: My antivirus program flagged AutoHotkey or a compiled script as malware. Is it really a virus?
False positives often occur each time a new version is released, as each release contains a new set of executable files that the antivirus vendors have never seen before. Fighting against these false positives is an uphill battle, as it requires submitting them to each antivirus vendor every time they occur. Each vendor has their own process for accepting and dealing with such submissions.
As a user of AutoHotkey, the best thing you can do if you encounter a possible false positive is submit the executable file to your antivirus vendor for analysis. They can then confirm that whether the file is actually infected and adjust their virus database accordingly.