Avast accidentally identifies Steam as a trojan

By on February 6, 2012, 5:30 PM

Just a quick heads up for Avast users: if you're having trouble opening Steam, your malware protection might be to blame. For over an hour Sunday morning, the free antivirus accidently flagged a Steam executable as a trojan and moved it to quarantine. More specifically, SteamService.exe was falsely recognized as Win32:Trojan.gen, preventing the distribution's client from running.

The Czech security firm corrected the problem within 90 minutes, removing the offending virus definition. It's unclear how the definition was released in the first place. Although the problem was swiftly addressed, you might still have to restore the file from Avast's quarantine to get things running properly again (you ought to find it in the "Virus Chest" of the "Maintenance" tab).

Updating Avast's definitions and/or manually restoring the affected files should work for a majority of you, but some users complain that their recovery process was a bit more involved, requiring a full reinstallation of Steam. That seems extreme but you have to go that route, be sure to back up your Steamapps folder (Steamsteamapps) so you don't have to redownload all your games.

High profile false positives aren't particularly rare. Just a few months ago, Microsoft's free antivirus identified Google's Chrome browser as Zeus, an online banking trojan. Thousands of users were affected by that snafu, including some businesses and school districts. In April 2010, a McAfee update caused a false positive of svchost.exe, bricking XP on thousands of enterprise computers.

User Comments: 13

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yukka, TechSpot Paladin, said:

This morning we had a problem with Internet Explorer being falsely spotted as malware/generic-S by Sophos. This was sorted out with an update not long after but not before alot of users called our helpdesk. Its not too common but does occasionally happen.

Darth Shiv Darth Shiv said:

Hilarious! What is steam doing that made them even consider it? That is the bit I don't get.

Kibaruk Kibaruk, TechSpot Paladin, said:

Good thing I uninstalled Avast, Microsoft Security Essentials are gaining a lot of ground and for good reasons

The5Xfactor said:

I also suspect Avast crashing my Steam (TF2) while playing. I am turning it OFF before starting Steam and so far no crashing!

Guest said:

Well my steam does have a lot of things hiding inside of it. They are games that I paid for an enjoy though....

Guest said:

they made a mistake. its origin thats the trojan.......

venomblade said:

Hm, I have Avast, no problems here with steam, wonder what's different..

Guest said:

Good know about the avast internet security.I am already using the COMODO Internet Security Pro 2012.It is really good.

dedparrot said:


Guest said:

Avast is not performing good now a days

treetops treetops said:

Avast eventually started taking days to scan idk if it was infected but I switched to avira and iv been happy ever since the end.

p.s. false positives happen no ones perfect, I just wish they would take wolf team off their lists, maybe they have by now i have not played in over a year but when I did I had to turn off avira, avast or avg in the past. I even wrote them emails.

mattfrompa mattfrompa said:

Been using Steam and Avast for years, no issues here. Avast has been great for me once I got it out of my face (no sounds, minimal pop ups)

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