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Incomplete Installation (#) Errors

When launching a game, I see "Completing installation..." and then "Incomplete Installation (#)".  What do I do?

Network Connectivity Issues

Internet or other network connectivity issues are the most common cause for encountering an "Incomplete Installation" error. Please visit the Troubleshooting Network Connectivity and Required Ports for Steam articles to ensure that your network is properly configured for Steam. Common error codes for connectivity issues include 3, 16, 20, and 35.

 

Common Error Codes 

Incomplete Installation (2)

Many of these issues were tied to FAT32 drives which has been corrected in a Steam update.

Some users have also reported moving the Steam installation to the default C:\ Drive will correct this issue.

If the issue persists, please contact Steam Support.
 

Incomplete Installation (3)

Steam can not connect to the internet.  Please see the Troubleshooting Network Connectivity article.
 

Incomplete Installation (10)

Steam servers are busy.  Please try again later.

 

Incomplete Installation (16)

Network timeout.  Please wait a few minutes and then try launching the game once more.  If the issue persists, please complete this guide.


Incomplete Installation (20)

Steam servers are unreachable.  This may mean Steam is experiencing technical difficulties. It may also be that your network needs to be properly configured for Steam.
 

Incomplete Installation (35)

Please ensure that the Required Ports for Steam are open.

 

Incomplete Installation (53)

IOLO System Mechanic Professional and F-Prot Antivirus are known to interfere with Steam and cause this error.  Please also try following the suggestions in the Delete of steam.exe failed, Win32 Error 5 Access is denied article. 


Incomplete Installation (55)

This issue can also occur on computers with Avast installed. You will need to configure Avast to ignore Steam itself and all Steam game files. Some users have had to uninstall Avast to resolve the issue.

This may also indicate a Steam Service failure.  Please try enabling the Steam Service:

  • Exit Steam.
  • Click Start > Run (Windows Key + R)
  • Type the following command:

    C:\Program Files (x86)\Steam\bin\Steamservice.exe /Install 

    (If you have installed Steam to another path, please replace C:\Program Files (x86)\Steam with the correct path.)

    This command requires administrator privileges and may take a few minutes.
  • Launch Steam and test the issue again. 

McAfee Security Scan is also known to create this error for Left 4 Dead 2. 

Problem with Steam?

Contact Steam Support