Proxy Server and CoCreateInstance Error


When installing SOLIDWORKS over the internet using an Installation Manager, or performing an update to a new version or service pack, you may encounter the following error depending on your system security or network proxy: cocreateinstance.png

Cause of the error

This error message often appears because of issues with your firewall, antivirus software or proxy server. In some cases, a proxy server might prohibit the SOLIDWORKS Installation Manager from downloading updates automatically or the installation files during the install process. It is also possible that your firewall settings prevent access to the download locations.

Another potential cause is that the SOLIDWORKS Background Downloader is running at the same time and is conflicting with the installation since SOLIDWORKS will think that two installations are running at the same time.


  1. Temporarily disable the SOLIDWORKS Background Downloader, Windows Firewall, and Anti-virus running on the computer.
    To disable the Background Downloader:
    • Click the SOLIDWORKS Background Downloader icon in the Windows® system tray, > click on ‘Disable Background Downloading’.
    To re-enable the Background Downloader:
    • Click on ‘Start’ > ‘All Programs’ > ‘SOLIDWORKS Installation Manager’ > ‘SOLIDWORKS Background Downloader’.
  2. Verify that any proxy servers running on your network allow connection to the SOLIDWORKS website and servers. A firewall might be in use and blocking the outbound communication from the sldimdownloader.exe process to the server as well. Make sure to:
    Allow outbound TCP connection to port 80 in the firewall for sldim.exe and sldimdownloader.exe (C:\Program Files\Common Files\SolidWorks Installation Manager).
    Allow full access to the following sites which the Installation Manager connects to for downloading:,, ( can be specified to include all sites)
  3. Uncheck the Installation Manager option, "Speed up downloads by using more network bandwidth"
  4. Run the installation using the installation manager as before.

If the error still occurs another workaround is to use the SOLIDWORKS installation DVD's or source files to complete the installation. These do not require connection to the SOLIDWORKS server to download the necessary files so it will not conflict with any proxy servers or firewalls.

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