2026.3.3 - Error when attempting to connect to Terminals

2026.3.3 - Error when attempting to connect to Terminals

avatar
mattmaxwell

Reproduce Bug:

  • Run > Terminals

  • Create new terminal (environments test: Integrated, PS7, PS5.1)

  • Connect to Terminal

Error Text:

XtermBlazor fit addon assets failed to initialize.
Error: XtermBlazor fit addon assets failed to initialize.
    at registerXtermFitAddon (https://<HOSTNAME>/assets/js/site.js?v=2026.3.3-37052641275:415:11)
    at async w.beginInvokeJSFromDotNet (https://<HOSTNAME>/_framework/blazor.server.js?v=2026.3.3-37052641275:1:4167)
    at async Xt._invokeClientMethod (https://<HOSTNAME>/_framework/blazor.server.js?v=2026.3.3-37052641275:1:67161)

   at Microsoft.JSInterop.JSRuntime.InvokeAsync[TValue](Int64 targetInstanceId, String identifier, JSCallType callType, Object[] args)
   at Microsoft.JSInterop.JSRuntimeExtensions.InvokeVoidAsync(IJSRuntime jsRuntime, String identifier, Object[] args)
   at PowerShellUniversal.PsuTerminal.OnAfterRenderAsync(Boolean firstRender) in D:\a\powershell-universal\powershell-universal\src\Universal.Server\Shared\Components\PsuTerminal.razor:line 144
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)

All Comments (1)

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Patrick Ouimet

Hello Matt,

Thank you for the clear steps and the full error text.

This is a known issue in PowerShell Universal 2026.3.3.

It happens when a code editor has already loaded in the same browser tab before you connect to the terminal, for example after you open a script or an app.

The editor changes how the page loads scripts, so the small add-on the terminal uses to size itself never registers.

The terminal then cannot start and shows the "fit addon assets failed to initialize" error.

The fix is done and will ship in the next release, 2026.3.4 (ticket PSU-1417, for internal reference only).

Until then, you can avoid the error this way:

Go to Run > Terminals and press F5 to reload the page.

Connect to your terminal before you open any script, app, or other code editor.

If you need an editor and a terminal at the same time, keep a second browser tab only for Terminals.

The same cause was reported for the admin console terminal, and you can follow that thread here: https://forum.devolutions.net/topics/56595/202632--admin-terminal-doesnt-open-on-all-pages

Terminals are documented here: https://docs.devolutions.net/powershell-universal/automation/terminals

If the error still shows right after a fresh F5 on the Terminals page, please tell us which browser you use and whether PowerShell Universal runs behind IIS or a reverse proxy.

Best regards,

Patrick Ouimet