What is zlclient.exe?

The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the zlclient.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.

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Zlclient.exe file information

Windows Task Manager with zlclient
Zlclient.exe process in Windows Task Manager

The process known as ZoneAlarm Client or Zone Labs Client belongs to software ZoneAlarm or ZoneAlarm Security Suite or ZoneAlarm Pro or Zone Labs Internet Security Utility or Mozilla Thunderbird by Zone Labs ( or Check Point Software Technologies LTD.

Description: Zlclient.exe is not essential for the Windows OS and causes relatively few problems. Zlclient.exe is located in a subfolder of "C:\Program Files"—mostly C:\Program Files\Zone Labs\ZoneAlarm\. Known file sizes on Windows 10/8/7/XP are 919,016 bytes (53% of all occurrences), 1,043,968 bytes and 10 more variants. 
There is an icon for this program on the taskbar next to the clock. The program has a visible window. The file is a Verisign signed file. The file has a digital signature. The software can be uninstalled in the Control Panel. The file is not a Windows core file. Therefore the technical security rating is 2% dangerous, however you should also read the user reviews.

Uninstalling this variant: The software vendor offers the option to get help from the software vendor Zonealarm, see if there is a newer version [1][2] or uninstall the program using the Control Panel ⇒ Uninstall a ProgramZoneAlarm or ZoneAlarm Pro.

Recommended: Identify zlclient.exe related errors

External information from Paul Collins:

Important: Some malware camouflages itself as zlclient.exe, particularly when located in the C:\Windows or C:\Windows\System32 folder. Therefore, you should check the zlclient.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


User Comments

"ZoneAlarm Pro" is a personal Firewall. It's blocks some simple computer functions. Therefore some network related programs could be hang up. Please be sure to use STM/ASI version 1.0e or higher if you have ZoneAlarm Pro installed.
  Matt   (further information)
Zone Labs Zone Alarme Pro (firewall)
Component of ZoneAlarm (also of the free version) and i guess the other versions too. Dont delete the process. Its ur firewall ;)
ZoneAlarm Pro is software based firewall.
Zone Lab's Zone Alarm Firewall. Can be Professional, Free Version, or Security Suite. Process keeps firewall active and protecting you from hackers, intrusions, etc.
Previously did not trust this part of Za as thought it to be an intrusive "phone home " applicationThese tips helpful esp. abou ZA pro. Thanks
This application appear to be the interface application used to configure Zonealarms actual firewall (TrueVector). I've notice the zlclient appears to start when a user logs in, but I have verified the firewall is actually running when no user is on.
  Mary C  
ZoneAlarm (firewall) component - - do not delete, unless you like being unprotected.
firewall software
Zone alarm PRO/Personal Firewall/Internet Security (all zone alarms).. Firewall...
  tezy   (further information)
Simply posessing the same filename as a beneficial utility doesn't necessitate a benign file. If this is inside your System32 directory, or inside of your (X):\Program Files\Zone Labs\Zone Alarm\Zone Alarm\[FILENAME.EXE] then it's bad- acts as a rootkit &/or backdoor
Zonealarm component 100% safe as long as only 1 instance of it is running.
It's part of the ZoneAlarm firewall. A very good firewall!
  Thomas Little  
Firewall, one of the best firewalls around
Zone Alarm Firewall
Harmeless as far as i know i have it and its a darn good firewall and its free
  Diego H.  
Vital ZoneAlarm component. Excellent software - I've used the free version for years.
  L. D.   (further information)
A good firewall, but eventually started locking up at startup and taking up 100% cpu time in bursts - caused huge slowdown in pc reaction. Shutting down the process fixed the problem.
After uninstalling Zone Alarm, zlclient still tries (and fails) to start. Not malware, but very annoying.

Rating chart

Summary: Average user rating of zlclient.exe: based on 27 votes with 19 user comments. 17 users think zlclient.exe is essential for Windows or an installed application. 2 users think it's probably harmless. 4 users think it's neither essential nor dangerous. 2 users suspect danger. 2 users think zlclient.exe is dangerous and recommend removing it.

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Best practices for resolving zlclient issues

A clean and tidy computer is the key requirement for avoiding problems with zlclient. This means running a scan for malware, cleaning your hard drive using cleanmgr and sfc /scannow, uninstalling programs that you no longer need, checking for Autostart programs (using msconfig) and enabling Windows' Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or, for Windows 8 and later versions, executing the DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the zlclient.exe process on your computer, the following programs have proven to be helpful: Security Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

zlclient.exe [all]