News from propellerhead site:

''A recent virus definition update for Norton Anti Virus detects our software titles Reason, ReCycle and ReFill packer as the backdoor.blarul virus. We have checked the software and as far as we can see, the software has not been tampered with after build time, meaning that any virus would be introduced as we compile the code, and that's unlikely.

Also, no other virus protection software detects these files as infected, so it looks like what Symantec calls a false positive, meaning that the files are being detected as infected even if they are not.

We have submitted the software in question to Symantec, who will investigate this further and hopefully give us a response shortly. We hope to have more information available by tomorrow.

To keep using our software in the meantime, you can set Norton Anti Virus to skip the Reason.exe, ReCycle.exe and ReFill packer.exe when scanning the system.''

Ive just had this problem as I use reason and norton. My antivirus quarantined reason.exe and I thought I would have to reinstall it all again...

Turns out its not a virus at all...