How To: Fix Zone Alarm (zclient.exe) High CPU Usage

Think 25% CPU usage is unacceptable for a software firewall? You’d be right.

Steps to fix:
– Ctrl + Shift + Right Click on Zone Alarm icon in the system tray and select Set debug level from the pop-up menu
– Set Debug Level to Off by clicking the appropriate radio button in the Set debug level window
– Click [OK]
– Restart Zone Alarm (i.e. quit then restart it)

Works on:
ZoneAlarm version:
TrueVector version:

Feel free to delete the stupendous amount of logging dirge left behind by Zone Alarm’s “writing phase” in C:\Windows\Internet Logs while you’re at it.

12 thoughts on “How To: Fix Zone Alarm (zclient.exe) High CPU Usage”

  1. The best way to fix it is as follows:

    Start –> Settings –> Control Panel
    Add/Remove Programs
    Find ZoneAlarm and press the remove button.

    I’ve found this works the best 100% of the time.. HAHAHAHAAHAHA

  2. Hey, thanks for fixing a very irritating problem. Yeah, what r3dux says. For instance, I fire up a cd ripper program and it wants to access the net. Why? I don’t let it. I have a hacked game on my PC. Guess why it wants to access the web? Nada. Not on my PC. Sorry.

    1. The CD ripper probably wants to talk to the CDDB/FreeDB servers to get artist/trackname info, so you could happily allow the ripper access while still blocking access to your hacked PC game, if you wanted.

      Glad to be of service :)

  3. Many thanks for this fix. I’ve been battering my brain with this issue. zlclient.exe was using 25-30 % of cpu. Now it has “calmed down”. Again. Many thanks. :)

  4. Thanks. Hopefully more will see this fix. Like it or not there are those who can only manage a zone alarm download.

    Henny Youngman: A man goes to a psychiatrist. “Nobody listens to me!” The doctor says, “Next!”

  5. the debug setting is not in the same place in v of the internet suite. any ideas on how to reduce za consumption of all available cpu?

    1. ‘fraid not, sorry – but my recommendation would be to get rid of Zone Alarm and just use Windows firewall.

      I used to use Zone Alarm on any Windows machines and virtual machines I used because it allowed me to control not only incoming connections (i.e. lock down all ports until a connection was asked for by an application) but outgoing connections (i.e. I don’t want this specific application to ever be allowed to connect to the net) – but it turns out that the firewall that comes with Windows 7 is actually pretty good, and can be configured to do all of that stuff.

      There’s plenty of material on how to configure it online, such as this:

      Also, once you’re ZA-less you won’t get all that nagging and updating rubbish, and iTunes will work properly (if you use it).

      And as a final bonus, your CPU usage will be back to normal ;)

    2. I may be a little to late but if you still have your issue, you can solve it(for me it worked at least) by going to zonealarm > firewall > basic firewall > choose the thing that says (X access attempts blocked.) This will open an Alerts and Logs interface. go to main and turn ‘event logging’ and ‘program logging’ off.

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