Avast Security Blogger

12 April 2011

Follow-up instructions for "False positive issue with virus defs 110411-1"

On 11 April 2011, virus definition update 110411-1 contained an error that resulted in a high number of ‘false positives’ – that is, clean websites or files being flagged as ‘infected’.

Our virus lab staff discovered the problem quickly, took precautions to stop more users from getting the wrong update and, about 45 minutes after the initial update, released a fix (update 110411-2).

About 4% of our user base was affected.

Although false positives are a fact of life, we sincerely apologize for any inconvenience caused to our community. If you were one who was affected by the bad update, after updating with a current virus definition file (as of this writing, update 110412-0), you should next:

  1. Open the avast! program
  2. Select “Maintenance”
  3. Select “Virus Chest”
  4. Sort by time moved to Chest
  5. Select files you wish to restore
  6. Right-click and select “Restore”

After the file restoral, copies of the files will remain in the Virus Chest.

We hope these steps will alleviate any confusion, but should anyone need further support, please visit avast.com/support.

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