Qlik Sense Desktop Problem - Error 1006 and [object CloseEvent]

[JorgeEsteso]

After updating Qlik Sense Desktop from Qlik Sense Desktop 2023 Patch 6 to May 2026 Patch 2, the application started losing communication with the local Qlik Engine.

Qlik Sense Desktop had previously worked correctly on the affected workstation. Immediately after the update, applications could no longer be used normally, even though the local Hub opened successfully.

The same Qlik Sense Desktop version worked correctly on other computers, so the issue appeared to be specific to this workstation.

Client System Information:
- Qlik Sense Desktop May 2026 Patch 2
- Windows 11
Server System Information:
- Qlik Sense May 2023 Patch 6
- Microsoft Windows Server 2022 Standard
- PostgreSQL 12.5

Error Description

When opening an application in Qlik Sense Desktop, the following error was displayed:

An error has occurred

Unable to connect to the Qlik Sense engine.
Possible causes: too many open connections, the service is offline, or there are network issues.

Error code: 1006

The Qlik Sense Desktop Hub could also be opened directly through:

http://127.0.0.1:4848/hub

However, when opening the Data Load Editor, the following message appeared:

Error

Error loading connections.

Details

[object CloseEvent]

The local ports were checked, and Qlik Sense Desktop was listening correctly over IPv4.

The Qlik Engine logs showed that the local Engine accepted the connection through 127.0.0.1:9076, but the client-side socket was closed shortly afterwards:

INFO	20260723T135829.175+0200	87856	71400	Personal\Me	default		0		20260723T135801.000+0200	TheServer: Registering new server session, SessionID=e22b8b60-373e-410e-9f21-1d582ad03a3d 
INFO	20260723T135829.176+0200	87856	71400	Personal\Me	default		0		20260723T135801.000+0200	QvSocket: Connected to server as user: 'Personal\Me' for session: '/app/enginedata' on socket 127.0.0.1:9076 <-> 127.0.0.1:55143 with ttl: 0
INFO	20260723T135829.183+0200	87856	71400	Personal\Me	default		e22b8b60-373e-410e-9f21-1d582ad03a3d		20260723T135801.000+0200	StdServer: OnRemoteClosed entered for socket 127.0.0.1:9076 <-> 127.0.0.1:55143, user: Personal\Me, app: .
INFO	20260723T135829.183+0200	87856	37492	Personal\Me	default		e22b8b60-373e-410e-9f21-1d582ad03a3d		20260723T135801.000+0200	Session stop reason: Socket closed by client

Root Cause

Based on the troubleshooting performed, this appears to be an environment-specific issue rather than a Qlik Sense Desktop product issue.

The same Qlik Sense Desktop version works correctly on other computers using the default installation paths, which indicates that the problem was specific to the affected workstation.

Qlik Support was unable to determine the exact root cause. However, the most likely explanations are:

• Corrupted or inaccessible data in the original Qlik Sense Desktop content folders.
• Incorrect or restrictive NTFS permissions.
• Windows profile configuration or folder redirection.
• Antivirus, endpoint protection or Controlled Folder Access interfering with the original paths.
• Corrupted files or remnants from previous installations.
• Another path-specific condition affecting the local Engine.

Resolution

After checking with Qlik Support and some testing, the solution is reinstalling Qlik Sense Desktop using the custom installation option and specifying application and content folders outside the default Windows profile paths.

The following folders were configured:

C:\WorkForQlikApp
C:\WorkForQlikContent

After installing Qlik Sense Desktop using these locations, the application started working correctly. The Data Load Editor opened normally and connections loaded successfully.

The WebSocket error 1006 was a symptom of the browser-based interface unexpectedly losing its connection to the local Engine. When the Engine cannot initialize correctly, access required files, or remain running, the interface can no longer communicate with it through the local WebSocket, resulting in errors

Reinstalling Qlik Sense Desktop with different installation and content directories created fresh folders with new files and permissions. This bypassed the environmental condition affecting the original default paths and allowed the Engine to start and maintain communication with the interface.

Hope this helps someone experiencing the same behaviour.