Frequently Asked Questions / Troubleshooting

How do I create non-standard resolutions in Windows with my NVIDIA GPU?

It is important to use the NVIDA Control Panel to change to a non-standard resolution. Using the Windows Display Manager will result in a corrupt desktop image.

What do I do if Windows shows a black screen instead of a login screen?

We’ve observed in Windows 2012 that the login screen will occasionally not appear until you hit the ‘Escape’ key.

Why does Google Chrome 61-62 show inaccurate colors?

Newer versions of Google Chrome (Chrome 61 and 62) use the ICC profile provided by the local OS rather than forcing its own color profile. This may make the colors appear different from what you may see in other browsers or in the Native Client.

As a workaround you can enter chrome://flags/#force-color-profile in your Chrome URL bar and select sRGB from the dropwdown. Then close and restart Chrome.

How many users can sign in at a time?

Scyld Cloud Workstation currently supports multiple signed in users at a time. Currently this defaults to 6. This value can be changed in the config XML file via the Server.ConcurrentClients.MaxClientCount option.

Can LDAP credentials be used at the sign in page?

Yes. There are two ways to support this.

Traditionally support for LDAP currently comes as part of the Scyld-Cloud-Manager package. Scyld Cloud Workstation can be configured to authenticate through Scyld-Cloud-Auth, which can talk to LDAP. To connect to a Scyld-Cloud-Auth service, open the config file, set Server.Auth.ScyldCloudAuth.URL, and add one or more Username elements to the Server.Auth.ScyldCloudAuth.Allow.

As of v6.1.0, Scyld Cloud Workstation passes credentials directly to the remote operating system. This feature is enabled by default, but it can be disabled by setting Server.Auth.OSAuthEnabled to false.

I’m only seeing a gray rectangle.

This is either caused by caching problems, an unsupported screen resolution, or an unexpected error between the client and server.

Try signing out, opening a new web browser, and trying again. If the problem persists, check the web browser’s JavaScript Console and the Scyld Cloud Workstation log file (Linux: /var/log/messages) for errors.

If you are a CentOS user, verify that Xorg is running on DISPLAY :0 by running ps aux | grep X. If you do not see a line that looks like Xorg :0, you may need to restart X by running init 3 and init 5 in CentOS.

If you are a Windows user and you are using the NvFBC videosource, verify that NvFBC is enabled by running NvFBCEnable.exe -checkstatus as an Administrator. If it is disabled, you can enable it with the NvFBCEnable.exe -enable command.

How do I press Ctrl+Alt+Del?

There is a shortcut button for this keyboard combination at the bottom of the Scyld Cloud Workstation video screen.

How do I press Ctrl+N, Ctrl+T, Ctrl+W, Ctrl+Tab, Ctrl+Page Up, or Ctrl+Page Down?

By default, Google Chrome (aka Chromium) intercepts certain specific keyboard combinations before Scyld Cloud Workstation can receive them. There is a special “app mode” available for Chrome users that can be activated at the command line by appending the --app=<url> flag. For example:

google-chrome --app=https://host/

This will open a borderless Chrome browser that will relay many of these key combinations to Scyld Cloud Workstation. If this is something you will do often, we recommend creating a shortcut with a flag to your Scyld Cloud Workstation host.


Certain keyboard combinations, such as Ctrl+Alt+Del and Alt+Tab are intercepted by the client operating system and are not relayed to the Scyld Cloud Workstation interface.

What ports do I need to open?

By default, Scyld Cloud Workstation must be able to accept incoming requests over HTTPS port 443 (or port 80 if you are using HTTP).

Can I run my applications?

Scyld Cloud Workstation is completely unaware of what applications are being run on the remote operating system. In other words, if your application can run directly on the remote host, it can be displayed on Scyld Cloud Workstation.

Will it run on my iPad / mobile device?

We do not yet officially support iPad or mobile devices, but we have had some success getting view-only functionality to work with an iPhone SE.

Is there audio support?

We do not support audio at this time, but please let us know if adding this feature would be important to you.

Can I cut, copy, and paste?

You can copy text from the local desktop to the remote desktop. See Paste Text from the Local Clipboard for more information.

What graphics cards do you support?

See Server Hardware.

How many NVIDIA GRID GPUs do I need?

As of v5.0, NVIDIA GRID GPUs are no longer required to run Scyld Cloud Workstation.

What do I do if Windows reports: “The program can’t start because LIBEAY32.dll is missing from your computer.”

This error message typically means that OpenSSL 1.1, which does not provide LIBEAY32.dll, is installed.

Scyld Cloud Workstation requires that an OpenSSL 1.0 compatible library (such as OpenSSL 1.0.1 or OpenSSL 1.0.2) is installed on the server side. OpenSSL will continue to receive security updates until December 31, 2019.

What Xorg.conf options do I need for an NVIDIA GRID / Tesla card over GPU passthrough?

First, find the appropriate BusID for your graphics card using the following command:

lspci | grep VGA | sed 's/\./:/'
00:07:0 VGA compatible controller: NVIDIA Corporation GK107GL [GRID K1] (rev a1)

The BusID is the first token 00:07:0. If you used lspci on its own, remember that periods must be replaced with colons before they can be used in an Xorg.conf file.

For older NVIDIA GRID cards (K1 or K2) add the BusID and the “UseDisplayDevice” “none” option. Modify the Xorg.conf file so that the Device and Screen sections look similar to the following:

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BusID          "00:07:0"

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "UseDisplayDevice" "none"
    SubSection     "Display"
        Virtual     1440 900
        Depth       24

For NVIDIA Tesla M60 users add the BusID (note: the syntax below is also valid). You may also want to specify a DPI (as needed) if images on the screen appear too wide or narrow. Modify the Xorg.conf file so that the Device section looks similar to the following:

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "Tesla M60"
    BusID          "PCI:0:07:0"
    Option         "DPI" "96x96"