Webplayer working offline?

I am attempting to run the webplayer on a machine that is offline (simply disconnected from the internet).

I can run the webplayer when the machine is connected, though as soon as it is disconnected I receive the error message “Failed to update Unity Web Player”.

I am using the 30-day trial of Unity Pro if that makes any difference.

The trial has nothing to do with it.

See this related answer by Graham:

Basically, Unity needs to download the player runtime and mono the first time it is run for a specific version of Unity. Once this is done, it can work offline, but it needs to install that first.

When building offline builds make sure you check the “offline deployment” option as otherwise the web page attempts to access UnityObject.js remotely.

So to clarify:

  1. You need to run online once to get the components installed correctly.
  2. You should check “offline deployment” in build settings.


Contains 3 folders


c:\Program Files (x86)\Unity

Contains 2 folders


I fixed this problem on another machine (this machine has never connected to the internet) by grabbing the cab file referenced in this answer:

After running the executable contained in the .cab there was a size difference between the folders of roughly 24MB. The difference is found in the ‘player’ folder located in the ‘WebPlayer’ folder.‘The Stable 3.x.x’ folder is added to the ‘player’ folder; now it works. Bizzare.

For me it seems it has something to do with what Release Channel is selected in the web player plugin.

I fixed my problem by doing the following:

  1. Make a webbuild (with build option offline deployment turned on)
  2. Turning on internet connection.
  3. Access the web build locally.
  4. Select Release Channel > Release (instead of Stable) by right clicking in the web player.
  5. Turn off the internet connection.
  6. Reload the web player html page.

Hope it works for you too.