VMware Horizon Idle Timeout: Which Timer Disconnected You

VMware Horizon, now sold as Omnissa Horizon, does not disconnect idle desktop sessions out of the box. When your session drops after a quiet spell, an administrator turned on a timer, or something outside Horizon ended it. There are five usual suspects: the Idle Time Until Disconnect (VDI) policy on the Horizon Agent, the Forcibly disconnect users limit in Horizon Console (600 minutes, or 10 hours, by default), a pool setting that logs you off after a disconnect, the Windows lock screen inside the virtual desktop, and your own laptop going to sleep. For Slack, Slack Green keeps your dot green from a server, so it stays green whatever happens to the Horizon session, free for 7 days with no card.

What resets the idle timer is input that the Horizon Client sends into the session: typing and mouse movement inside the Horizon window. Work in local apps on your laptop does not count, because Horizon never sees it.

The Citrix version of this page is how to keep a Citrix session active.

Which Horizon timeout hit you?

Two of these catch people out. The 10-hour Forcibly disconnect users limit is a session length cap, not an idle timer, so it disconnects you even in the middle of typing. And the Windows lock inside the virtual desktop is not Horizon at all: the session stays connected, but Windows in the VM locks itself like any office PC. That lock, and how to read the policy behind it, is in why a Windows PC locks after 15 minutes.

A Horizon desktop that stays connected still shows you away in Slack 10 minutes after your last keyboard or mouse input in it. A server-side tool keeps your Slack dot green with no input, even with no Horizon session open.

The Horizon idle policy: Idle Time Until Disconnect (VDI)

Horizon 7.10 added an idle timer for virtual desktops as a group policy in the Horizon Agent ADMX template: Idle Time Until Disconnect (VDI), under VMware View Agent Configuration, Agent Configuration. It is not configured by default. When an admin sets it, the agent disconnects the session after that many minutes without input.

A disconnect is not a logoff. Your apps keep running in the desktop and you can reconnect to find them as you left them. A second policy, Disconnect Session Time Limit (VDI), or the pool's Automatically logoff after disconnect setting, decides how long a disconnected session waits before Windows logs you off and closes everything.

What counts as activity in a Horizon session

The idle timer runs on the Horizon Agent in the virtual desktop, so it only sees input that arrives there:

• • Typing or moving the mouse inside the Horizon Client window counts.
• • Work in apps on your own laptop does not count.
• • A video, a long report or a download running inside the desktop does not count.
• • A keep-awake app on your laptop, such as Caffeine or Amphetamine, blocks your laptop's sleep but sends no input.
• • Input while the Horizon window is minimized does not reach the session.

How to keep a Horizon session from timing out

• Keep your own computer awake. If your laptop sleeps, the connection breaks, whatever the Horizon timers say. See how to stop a computer from sleeping.
• Keep the Horizon window in front when you step away for a few minutes. A USB or software mouse jiggler on your laptop then moves the pointer inside the session, and that counts as input.
• Reconnect instead of starting over. After an idle disconnect, open the Horizon Client and connect to the same desktop. Your apps are still there until the logoff timer runs out.
• Ask IT for a longer idle time if your work involves long reads or calls in the desktop. The idle policy, the discard SSO setting and the pool logoff are all admin choices, set for security or to free up virtual machines.

Do not try to change Horizon policies inside the virtual desktop. They come from group policy and return at the next refresh.

For Horizon admins: where the timers live

Set the idle disconnect a little longer than the Windows lock inside the desktop, so users see a lock screen they can clear before the session drops.

Horizon and your chat status

If Slack or Teams runs inside the virtual desktop, its status follows your input in the desktop, not on your laptop. The Slack desktop app counts keyboard and mouse input anywhere on the computer it runs on and sets you away after 10 minutes without it, and a disconnected desktop sends none. Details in how to keep a remote desktop session active.

FAQ

Why does my Horizon session disconnect after 10 hours? The Forcibly disconnect users global setting defaults to 600 minutes. It caps session length whether you are active or not. Only an admin can change it.

Does VMware Horizon have an idle timeout? Not by default. Admins add one with the Idle Time Until Disconnect (VDI) agent policy, available since Horizon 7.10.

Is Omnissa Horizon the same as VMware Horizon? Yes. VMware's end-user computing business, Horizon included, became Omnissa in 2024. The settings and policy names are the same.

Does a mouse jiggler keep a Horizon session active? Only if the pointer is over the Horizon window, so its movement reaches the virtual desktop. Many IT policies forbid jigglers; check yours.