Omnissa Horizon Client for Mac Release Notes

Horizon Client for Mac 2603 | 14 APR 2026

Check for additions and updates to these release notes.

With Horizon® Client™ for Mac, you can access remote desktops and published applications from your Mac with the best possible user experience on the Local Area Network (LAN) or across a Wide Area Network (WAN).

What's New

Horizon Client for Mac 2603 is released in conjunction with Horizon 8 2603.
Added support for end users to immediately disconnect from a remote desktop or application session by pressing the Ctrl+Alt+F12 keyboard shortcut. This feature is disabled by default. Administrators can enable it through the viewClient.enableSessionDisconnectHotKey setting.

Before You Begin

Horizon Client for Mac requires a macOS Sonoma (14.x), macOS Sequoia (15.x), or macOS Tahoe (26.x) operating system running on a 64-bit Intel-based Mac or ARM-based Mac.
Horizon Client for Mac is supported with the latest maintenance release of the following deployment types:
- Horizon 8 version 2006 and later
- Horizon Cloud Service - next-gen
- Horizon Cloud in Microsoft Azure
To install Horizon Client for Mac, download the disk image file from Omnissa Customer Connect. For system requirements and installation instructions, see the Horizon Client for Mac Guide.
Beginning with Horizon Client for Mac 2006, Virtual Printing (also known as ThinPrint) is not supported. Use Horizon Integrated Printing instead.

Limitations

This release may not work with existing Nuance and Imprivata integrations.

Resolved Issues

AST-11503: Users unable to launch Horizon VDIs after upgrading Horizon client to version 2512
AST-15953: URL redirection issue with published app that launches Epic EMR

Known Issues

Displays and Keyboards

Teams Optimization

When using the Omnissa Horizon Client for macOS with an R0 Teams account, the Notepad application flickers continuously after being shared in a Microsoft Teams meeting. The entire shared application viewport flickers throughout the session. This issue occurs only when Teams Optimization is active.

Workaround: None.
Flickering Headers for MSTeams

Under MS Teams optimization, the sharing of browser applications like Chrome or Edge from an RDSH/VDI environment can lead to header flickering. This is a visual disruption that is also visible to Mac clients.

Workaround: None.
Desktop stops responding when you connect to a remote desktop with the Blast display protocol

When you connect to a remote desktop with the Horizon Blast display protocol from a Mac client system that has an NVIDIA GeForce GT 755M graphics card, the desktop stops responding.

Workaround: None. This is a third-party issue.
Auto-fit does not work for the remote desktop if you change the display to full resolution.

If you launch a remote desktop with the PCoIP display protocol in full-screen or window mode on an iMac with a Retina or monitor that supports a 5K display, and the screen size is more than 4K (4096 x 2160), auto-fit does not work for the remote desktop if you change the display to full resolution.

Workaround: None. This problem is caused by a PCoIP limitation.
Remote desktop does not start if you start a remote desktop with the Horizon Blast display protocol in full-screen or window mode

If you start a remote desktop with the Horizon Blast display protocol in full-screen or window mode on an iMac that has a Retina display or a monitor that supports a 5K display with Full Resolution mode, and then disconnect and reconnect with the PCoIP display protocol, the connection fails and the remote desktop does not start.

Workaround: This problem is caused by a PCoIP limitation. Change to Normal mode and use the PCoIP or Horizon Blast display protocol.

Smart Card Authentication

Some .net smart cards fail to authenticate to Connection Server over a TLS 1.3 connection
Some .net smart cards do not support the RSA-X-509 mechanism, which is required by TLS 1.3. To determine if your smart card supports RSA-X-509, run the command pkcs11-tools --module xxx -M.

Workaround: Use TLS 1.2 to connect to the Connection Server.
TokenD support for physical smart cards does not work

TokenD support for physical smart cards does not work well with macOS Catalina 10.15.4 and later.

Workaround: Use CTK instead, or modify the following option to enable TokenD support:
```
#sudo defaults write /Library/Preferences/com.apple.security.smartcard Legacy -bool true
```
Client might not verify smart card's PIN during server authentication when the smart card PIN is cached

With the IDPrime .Net card, when the SafeNet Authentication Client middleware is installed, you can view or change the smart card's cache type. If the cache type for the IDPrime .Net card is "Normal Cache," the client might not verify the smart card's PIN during server authentication when the smart card PIN is cached.

Workaround: Change the Cache Type to "Always Prompt" for the IDPrime .Net card. This setting enables the client to verify the smart card's PIN each time the user connects to the server.
Horizon Client might stop responding when you connect to a server that has a valid root-signed certificate

If you set the Horizon Client security preference ( Horizon Client > Preferences > Security) to Do not verify server identity certificates and connect to a server that has a valid root-signed certificate, Horizon Client might stop responding.

Workaround: Unplug the smart card reader and then plug it back in.
Smart card authentication issues

On macOS 10.15 or later, if you are using a TokenD driver, the Keychain Access app does not refresh when you unplug and re-plug in a smart card/smart card reader, and the Mac client cannot obtain the update status for the smart card. Because of this issue, the following problems might occur in Horizon Client on macOS 10.15 or later:
- Smart card authentication does not work after you unplug and re-plug in a smart card/smart card reader.
- Smart card redirection might not work after you unplug and re-plug in a smart card/smart card reader several times.
- The Disconnect user sessions on smart card removal option in Horizon Console does not work.
- The smart card removal policy on the agent machine might not work.
Workaround: Switch to the CryptoTokenKit driver on macOS 10.15 or later. If you want to continue using the TokenD driver, for the smart card authentication issue, quit both Keychain Access and the Horizon Client app, relaunch Horizon Client, and perform smart card authentication again, making sure that Keychain Access is not launched. For the smart card redirection issue, reboot the Mac client machine, launch Horizon Client, and perform smart card authentication again, making sure that Keychain Access isn't launched. There is no workaround for the smart card removal policy issue with a TokenD driver.

Touch Bar

Focus for the front window is lost when switching between published applications that are hosted on Windows Server 2016

You might lose focus for the front window when you use the Touch Bar to switch between published applications that are hosted on Windows Server 2016. This problem can also occur when you press Command+~, or click the dock icon, to switch windows. This problem typically only occurs after switching windows several times.

Workaround: Use the mouse to click the window and regain focus.

USB Redirection

System Extension Blocked error

When you start the USB service on a macOS 10.15 or later system, the System Extension Blocked dialog box appears.

Workaround: Click OK in the System Extension Block dialog box, navigate to System Preferences > Security & Privacy, and allow the extension to load.
Connecting password-protected storage devices might not work correctly

If you use the PCoIP display protocol, connecting some password-protected storage devices (such as IronKey USB flash drives) might not work correctly. For example, after you redirect the device to the remote desktop, the password prompt does not appear. The remote desktop shows that a new drive was added and so displays a new drive letter but no corresponding label to identify the device.

Workaround: Configure Horizon Client to automatically connect the device when you insert it. From the Horizon Client menu bar, select Desktop > USB > Autoconnect USB Devices on Insert.
Files that you copy or move to the drive do not appear on the drive when using the USB redirection feature

If you use the USB redirection feature to connect a Transcend USB 3.0 external hard drive to a remote desktop from your Mac client system, files that you copy or move to the drive do not appear on the drive after you disconnect the drive from the remote desktop.

Workaround: Redirect the external hard drive to the remote desktop again. The files appear on the drive.
Agent unreachable error

When you connect to a Windows remote desktop, start USB services, redirect a USB storage device to the remote desktop, disconnect from the remote desktop, and then try to reconnect to the remote desktop, either USB services are not available in the remote desktop or you cannot reconnect to the remote desktop. In Horizon Console, the state of the machine is Agent unreachable.

Workaround: If you are an end user, restart Horizon Client and try again. If you are a Horizon administrator, restart Horizon Agent in the machine.
Desktop connection is sometimes disconnected when the USB "Automatically connect at startup" setting is enabled

After you connect to a remote desktop with the USB Automatically connect at startup setting enabled, the desktop connection is sometimes disconnected.

Workaround: None.

Miscellaneous

.NET-based smart card authentication does not support on TLS 1.3.

Workaround: Use TLS 1.2 for .NET cards.
Launching applications from a second CPA disconnects the existing session

If you first connect to a pod in a Cloud Pod Architecture (CPA1) and launch an application, you can open multiple applications within CPA1. If you then launch an application from a different pod (CPA2), a new session is created for CPA2. When you attempt to open an additional application from CPA2, the existing CPA2 session is disconnected.

Workaround: None.
Scanner property 'Black and White' Option is blocked on Mac OS version 13.5.2 with Horizon Scanner Redirection

Workaround: Use a Mac OS version other than version 13.5.2. See KB 95187.
Moom user interface does not work

The Moom user interface does not work for UWP published applications.

Workaround: None.
Cannot start a Omnissa App Volumes application

You cannot start a Omnissa App Volumes application from the Dock on the client system.

Workaround: Start the application from Horizon Client, or use a shortcut.
Horizon Client for Mac stops responding

Horizon Client for Mac stops responding if you unplug an external graphics processing unit (GPU).

Workaround: None.
Moom UI does not appear when you hover your mouse over the Maximize icon

With Moom 3.2.12 (3240), the Moom UI appears when you hover your mouse over the Close icon, not the maximize icon, in Office 2016 and 2019 apps.

Workaround: None.
Response time of Windows Server 2016 hosted remote applications is slow

On late 2016 MacBook Pro client systems, the response time of Windows Server 2016 hosted remote applications is slow in the first few seconds after you launch a Windows Server 2016 application or switch the top window between Horizon Client and the Windows Server 2016 application window.

Workaround: None. This is a third-party issue.
Cannot log in to the same server as a different user when "Remember this password" is selected

If you select the Remember this password check box when you log in to a server, you cannot log in to the same server as a different user if the credential caching timeout period (clientCredentialCacheTimeout) on the server has not yet expired. Horizon Client will automatically use the saved credentials to log you in to the server.

Workaround: Remove the server from the Selector window (right-click the server icon and select the Delete menu item), click the Add Server button to add the server again, and then log in to the server as the different user.
Unexpected results can occur if you edit an application pool in Horizon Console and change the path to point to a different application

If an administrator edits an application pool in Horizon Console and changes the path to point to a different application that already has an application pool associated with it, unexpected results can occur. For example, the original application might be launched from the Mac Dock instead of the new application.

Workaround: Make sure that each application in a farm is associated with only one application pool.
Changes to webcam and audio devices are not detected

Changes to webcam and audio devices that are connected to, or disconnected from, the Mac client system during a remote desktop session are not detected by the Real-Time Audio-Video feature.

Workaround: Disconnect and reconnect to your remote desktop session to detect webcam and audio device changes. For example, if you connect a USB headset to the Mac client system during a remote desktop session and you want to use that headset on the remote desktop, you must disconnect and reconnect to the remote desktop session to make the headset available.
Screen-share of Microsoft Teams as RDSH application shows desktop wallpaper only

When you screen-share an RDSH application session of Microsoft Teams, only the desktop wallpaper appears in the screen-share preview and the recipient's screen-share. The application window and desktop icons are not displayed. This issue occurs when Horizon Client is not enabled to record screen contents.

Workaround: Go to the macOS system settings. Under Screen & System Audio Recording, enable Horizon Client to record the content of your screen and audio.

Documentation

Horizon Client for Mac documentation is in the Omnissa Information Hub.

Localized Content for Omnissa Docs

For details on Omnissa's localization strategy, see KB article "Announcing Omnissa Localization Support".

Support Contact Information

To receive support and to learn about support policies, see Omnissa Customer Connect.

For information on filing a support request in Customer Connect and via Cloud Services Portal, see the Omnissa knowledge base article at https://kb.omnissa.com/s/article/2006985.

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