Error "See tabadmin.log for details." and Conflicting Ports After Attempting to Reconfigure (or Install) Tableau Server

Published: 04 Oct 2017
Last Modified Date: 03 May 2019


When trying to reconfigure (or install) Tableau Server, you may get the error message 
Blocked or conflicting ports found on [Machine Hostname or IP]. See tabadmin.log for details.
Unable to determine if all components of the service started properly. See "tabadmin.log" for more information.

If this was in response to a config change made on a worker node, or to adding a new worker node to a cluster, the error may instead say  See worker tabadmin.log for details .

After running "netstat -aon | findstr 0.0:80" to check what process is holding port 80, PID = 4  (SYSTEM) is showed, but no IIS or MSSQLSERVER is running on this machine.


  • Tableau Server 
  • Windows OS


Try one of the following options with your IT team and/or Tableau Server Administrator.

Option 1

Disable http.sys by running "net stop http". This will work, but will disable any other services that are dependent on http.sys.

Option 2

  1. Run "net stop http" and record the list of dependencies that Windows displays when you try to stop http.sys.
  2. Then find then new service that is causing http.sys to activate, and disable that service.
    • It is often Microsoft Web Deployment Agent Service, which is now "bundled" with some Microsoft updates.
    • This service is set to auto-start without any user agreement or input and you may not notice when it was installed.
  3. Once the service that is using http.sys is disabled, you can run a "net start http"  to re-enable http.sys.


    Windows has a service called 'http.sys' which will seize port 80. It does this so that it can provide multiplexed port 80 access to other processes. Often this 'other' process is IIS or MSSSQLSERVER, but other process may also use http.sys in this way. They include W3SVC, Print Spooler, SSPD Discovery, Windows Remote Management, Branch Cache, and Microsoft Web Deployment Agent Service (among others).

    The Gateway component of Tableau Server is an Apache HTTPD web-server.  It needs to bind directly to port 80, which it cannot do if http.sys has already done so.
    Did this article resolve the issue?