See if this helps.
Resolution for Issue ‘My Avast free version is now blocking QB. avast antivirus antivirus is active on this computer and may be blocking quickbooks. Is there a fix for this?’ available: Yes (Solved).
Source: Intuit Community forum.
My Avast free version is now blocking QB. avast antivirus antivirus is active on this computer and may be blocking quickbooks. Is there a fix for this?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.
