Avast hangs my system on detection of (false positive) virus.

Avast 2014.9.0.2021 (140812-3) WinXP Pro x86/32 on two identical systems.

A program I wrote myself and is unchanged for months suddenly produces a false positive.
System 1: OK, no problem, click the popup link and set it as false positive - back to normal.

System 2: System hangs (actually drops to a crawl), no popup dialog to fix problem, system unusable.

Obviously I don’t want to uninstall Avast before running my program, but what can I do ?

is it a Win32:Evo-gen (susp) = Suspicious detection?

you can report it to avast lab here http://www.avast.com/contact-form.php

does exluding help http://www.avast.com/en-eu/faq.php?q=exlusion#searchForm

Er, I did this of course on system 1 which worked ok. (I have now done it again via your link).

A temporary fix seems to be to use the debug version of my program on system 2.

How long will it be before I can run the normal version again, and why does it hang my system anyway ?
I assume any detection on system 2 will result in a 30 minute reboot ?

if you want one of the experts here to have a look inside, you may attach a diagnostic log

see instructions here https://forum.avast.com/index.php?topic=53253.0
scroll down to Farbar Recovery Scan Tool and attach the logs (two logs) here … then Essexboy will have a look when online