Tuesday, November 20, 2007

HP "Net Driver HPZ12" Service Causing Explorer Hang

I've just about had it with Hewlett-Packard and their Photosmart C6180 All-in-One. One of my biggest problems can be found on HP's IT Resource Center forums, in replies to "Photosmart C6180 - the usual problems". There are at least dozens of people reporting the same driver-related problems with this device, probably affecting hundreds of users. I bought mine new off the retail shelf less than a year ago, and HP doesn't seem to give $0.02 about any of our problems, even after countless emails, online chats, phone calls, and escalations. (Though the HP software has progressed from version 7.x to version 9.x in that time, only the 7.x version is still compatible with the C6180, and not even a service release has been made available.)

Many of the problems are related to the network support, particularly with scanning. I've already decided that fighting with the full scanning support usually isn't worth the time, but this problem isn't related to the scanning. (And for the moment, even after this ordeal, the scanning appears to be mostly working!)

The symptoms:

I was just doing nothing out of the ordinary under Windows XP, and noticed that Explorer (the shell) was terribly sluggish. Opening a new "Windows Explorer" window took 30+ seconds. Interestingly, the desktop icons usually remained active, while the taskbar would appear hung. Other applications appeared unaffected.

On anyone else's computer, I'd suspect malware (viruses/worms/spyware/etc.). I did a few checks just to make sure nothing was amiss. My current user account was a non-administrator, and even running as another test user had the same disappointing results.

There are a number of issues that can cause Windows Explorer to "hang", which almost all take some time to diagnose and fix, if even possible without a new user profile, or in extreme cases, a reinstall of Windows.

The fix:

After a bit of experimenting, I finally started stopping and disabling some of the Windows services. Stopping and disabling the "Net Driver HPZ12" finally fixed the hang issue. Interestingly, there is also a different "Pml Driver HPZ12" service that I was able to leave running without any noticeable issues.

Update (2008-10-26):

This page now has over 1,300 page views, and is currently the most visited post on this blog! (If only HP would take notice, and just fix the issues...)

I feel obliged to mention, I've found new hope for my HPC6180 as I was working on my Ubuntu Linux Router Upgrade Project. Not only is the printer functionality comprehensively supported, but also the scanner, and apparently even the fax! While I'll share the details in a future post, the make and model configured in my "Printer configuration" applet shows as "HP PhotoSmart C6100 Foomatic/hpijs, hpijs 2.8.2.z". The scanner works with the "XSane Image Scanner" (0.995) applet.


Anonymous said...

Hi Mark,
could you please give me more details about how you fixed the problem?
thank u,

Mark A. Ziesemer said...

lu - What details are you looking for exactly? If it's how to stop/disable a Windows service, click on the link in the post, as Wikipedia has some decent instructions.

Anonymous said...

Hey, this fixed my molasses ridden machine. IE etc pop open like they used to. I was hunting for a virus or worm or trojan and found this HPZ12 service. Just had a runaround over a new hp portable printer that I ended up returning. Wouldn't you know HPs behind the hangup I had!!!

Anonymous said...

I gained 200MB of idle RAM back

Anonymous said...


Thank you so much for your posting. It really helped.

I ran into the same problem for the past week with my HP Pavilion running Vista SP1. I was getting "Host Process for windows services stopped working and was closed" error message and then my IE started to run really slow.

After disabling the HPZ12 service, I got my computer back.

Thank you.


Anonymous said...


BWT, what is the HPZ12 driver for? Do we need it for normal operations? If we do, is there a new version we should be installing?



Mark A. Ziesemer said...

It seems mostly related to HP's tray monitor, the "HP Digital Imaging Monitor", which I also normally disable.

I found some more information at http://www.answersthatwork.com/Tasklist_pages/tasklist_h.htm , which includes a claim that HP themselves stated that "Most if not all printing functions will work without it, and print quality and speed are not affected by this."

Anonymous said...


got to leave this message, because i was suffering the same problem!

now, my mood is a bit better ;-) !


Anonymous said...

Excellent ! A few months ago I bought an HP 7120, and I've been having this same problem off and on, though I hadn't made the correlation.

Thanks for the tip !

Anonymous said...

Wow. Months of bitching at Windows Explorer and IE and it was that piece of crap from HP the whole time.

Anonymous said...

I reinstalled my XP machine because it was running so slowly but installed the smaller driver package from HP ~30Mb instead of 200Mb. This must have been the problem I was having. 200Mb for a print driver!

Anonymous said...

I have an HP L7590 printer. Soon after installing it, I noticed that about every 2-3 days my email and browser would suddenly be unable to connect. I finally installed SysInternals Process Explorer and tracked it down to HPZimp12.dll which seems to leak about 10k of memory every 5-10 seconds...even when I'm not even doing anything on the computer. Killing the process suddenly breaks everything loose and the dll automagically restarts itself to start the whole cycle over again.

From what I'm reading here, it doesn't seem worth my time to open a ticket with HP. That's just plain pathetic.

brian said...

Many thanks Mark.
Event Log was cluttered every five seconds with 7035/7036 errors/HPZ12. PC appeared to be OK other than this. Disabled in the tray and errors stopped immediate. Printer still works fine too. Can this disable be made permanent? ( I am not a pc whizz kid but know my way around a nadge).

Anonymous said...

Nice Mark...

Pandora on IE7 choppy on Vista Ultimate x64

IP-access to: HP AIO & HP-LaserJet

Alter PML service
Disabling, then performing a STOP was effective solution.

...manually stopped svchost after watching pslist, then found ur blog post.

Best Regards

Anonymous said...

Hi Mark!
Excellent post.
Finally I have found the solution, with the help of your Post, for my problem.
Opening Exel or Word files with double clicking on them, was very-very slow (more than a minute).
But opening the same file from within the Excel or the Word, it takes only a few seconds.
This happened after installing HP C6180 printer, using Network access instead of USB.
But after simple stopping "Net Driver HPZ12" process, the above problem disappeared, and the opening file with double click worked fine again.
Thanks your post again

Anonymous said...

Many thanks,
Same issue with an HP C7280. I put the service on manual, which frees 143MB of RAM and a chunk of cpu time.

Christian SALLES said...

Thank you MarK

Your advice is great even if I had trouble finding because when you type Hangapp on a search engine, unfortunately I did not find your site ..

Since October, Hangapp freezes regurlay my desktop with Firefox, but IE Photoshop or ACDSee ..

After reading your post, I desinstalled all the stuff related to HP Photosmart C7280 All-in-One Printer, Fax, Scanner, Copier

http://www.shopping.hp.com/store/product/product_detail/CC567A% 2523ABA

I even deleted manually still more than 86 files HPZ .. and Hangapp in the registry table ..
But I have still Hang with this message in French

Application bloquée PhotoshopElementsEditor.exe, version, module bloqué hungapp, version, adresse de blocage 0x00000000.

Pour plus d'informations, consultez le centre Aide et support à l'adresse http://go.microsoft.com/fwlink/events.asp.

Do you have any clue or idea how to solve the problem

Anonymous said...

was having issues since i instlled some hp driver crap too. this helped, thanks !

Jason Proctor said...

You can disable the PML Driver HPZ12 two ways that I know of:

1) you can disable it using regedit:
set HKLM\SYSTEM\CurrentControlSet\Services\Pml Driver HPZ12\Start
to 3 for "manual" startup, or to 4 for "disabled".
2) you can run services.msc from the run dialog box or from the command line and disable the service PML Driver HPZ12

Hope this helps

MrNutsy said...


I know I am posting a little late to this, but I wanted to let you know I feel your pain!

As an admin of over 100 Windows servers, not to mention assoicated desktops, we run into this issue on a regular basis.

A trick I have deveolped in avoiding the installaiton of "extra" software (that is, not just the drivers) is to download the HOST-BASED drivers, even on desktops. These are typically drivers only and do not include the monitoring software.

If the printer does not have host-based drivers listed, download the application and start to run. I will extract the files - usually to C:\temp, but not always, so look for the location as it is extratcing it - then I will copy the files from the temp location to a permanent location on the hard drive. I use C:\Drivers\HP\printername to keep track of the drivers easier.

I will then install the printer, choosing the option of Have Disk on the driver selection screen, then browing over to the newly created location and installing the drivers from there.

It takes an extra couple of minutes, but it save a lot of headaches in the long run!

Anonymous said...

I talked to an HP rep who said he believes this service gathers system information, installed programs, files, etc and sends info to HP to help them better support their software. They use the information to improve their software by knowing about your system and what other software theirs is running alongside. He said disabling the service causes no harm. I don't know if the function is true, but disabling the service got my computer back to functioning normally. This service was taking all my CPU.

Ajd394 said...

this issue is resolved by the update "Critical Update to Enhance Reliability of Network and USB Connectivity and Improve System Responsiveness While Printing"

Anonymous said...

Thanks for the info. I also found this old news. http://searchtasks.answersthatwork.com/tasklist.php?File=PML%20Driver%20HPZ

The original driver worked without problem, but memory and cpu hogging started after my last hp updates for laptop and printer. I'm using HP pavilion+hp Photosmart C4200. I guess i should not use their update service programs rather donwload only new drivers and software updates when problem occurs.

Anonymous said...

I am a (again) happy owner of a HP C7280.

My system is back to life after a long long time of slowness...

P.S.: I've also turned to "manual" the services: HP CUE DeviceDiscovery and Service
HP Network Devices Support. If they are marked as "automatic", xp startup lasts forever...

Thank you Mark!
Danke schon!!!


Anonymous said...

"Critical Update to Enhance Reliability of Network and USB Connectivity and Improve System Responsiveness While Printing"

The above update has nothing to do with the problems we are talking about...

Anonymous said...

Thank you, Mark. Disabling those services instantly made my laptop go silent. Before, my laptop's fan was like a jet engine on full thrust. Now it is idling.

Anonymous said...

Yes, lots of issues with the HP Soft (Crap-)ware. Thats why finaly bought a Brother. Saves nerves and (a lot of) money.

Anonymous said...

Hi Mark,
Installed new printer weeks ago but did not get this problem until one ink cartridge got low. Found the fix the hard way, then searched the driver name and found your blog. Great to know guys like you are willing to help wantabe ITT's like me.

Monica said...

Thank you, thank you, THANK YOU! I bought my HP Officejet Pro 8500 last May. Just in the last 2-3 weeks, Firefox has been painfully slow to open. A few, but not all, apps as well. Nothing I tried helped. There was no spyware, viruses, etc. I need to defrag but this didn't feel like a fragmented hdd problem. Tonight I checked my services after my hdd went bonkers for two minutes. Found both the HPZ12 and the PML Driver HPZ12. Those are new so I did a Google search. Found your site :) All the comments had me convinced it was my printer but couldn't figure out why it was just now causing a problem. Then I read the very last comment. The problem started about the same time I got a low ink warning (my first one). I've changed the services to manual. FF is popping open in about 3 seconds instead of 25 to 30 :o Whew!!

Monica said...

I had to put these services on manual. Disabling them rendered my scanner (and probably other components) useless. I tried to scan and got a message on the printer (to the effect) that no devices were found/couldn't connect to the printer.

Anonymous said...

Thank you so much for your posting. It really helped.

I deactivated the Service and no more explorer hang.

MCCJim said...

From different web sites it seems the PML is required when querying ink levels.
The HPZ is to prevent the computer from going into hibernation mode.
After reading the below I disabled it, removed it from the registry and what associted files I could find.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost (Reg_mult_sz HPZ12)

From http://www.securityfocus.com/bid/21935/info
An attacker may exploit this issue by gaining local access to an affected computer and issuing the following commands:

C:\sc config "pml driver hpz12" binpath= D:\attack\attack.exe
C:\sc start "pml driver hpz12"

HP Multiple Products PML Driver HPZ12 Local Privilege Escalation Vulnerability

Bugtraq ID: 21935
Class: Design Error
CVE: CVE-2007-0161

Remote: No
Local: Yes
Published: Jan 08 2007 12:00AM
Updated: Nov 27 2007 06:13PM
Credit: Sowhat is credited with the discovery of this vulnerability.
Vulnerable: HP PSC 900 0
HP PSC 700 0
HP PSC 2510 Photosmart Printer
HP PSC 2500 Photosmart All-in-one 0
HP PSC 2400 Photosmart All-in-one 0
HP PSC 2200 0
HP PSC 2100 0
HP PSC 1300 0
HP PSC 1210 All-in-One 0
HP PSC 1200 0
HP PSC 1100 0
HP PML Driver HPZ12 0
HP Officejet K 0
HP Officejet G 0
HP Officejet D 0
HP Officejet 7100 0
HP Officejet 6100 0
HP Officejet 5500 0
HP Officejet 5100 0
HP Officejet 4100 0
HP Color LaserJet 4650

sandy_pats said...

Dear Mark

Thanks a million... I had the hang up problem too and had searched on diff blogs and forums... Man U did that for me.... Thanks... U are my Almighty

Anonymous said...

thanks man, Y.A.L.S.
or , you're my friend's life saver to be more specific.(just fixed her problem)

Anonymous said...

Thanks dude, you should see the nightmare having this on a Terminal Server!

Unknown said...

Am using hp 1210 all in one printer from last 5 years now, and I’ve never been unhappy with this printer. The print quality is very good, is equal to photo print quality and it is easy to use,

But here the thing is am update my system from windows xp to windows vista. The printer is working fine, but is unable to scan the images through the scanner.
So am unable to fiend any supported software for scanning support of the Hp 1220 printer at hp.com. just now I downloaded hp 1210 all in one printer scanner driver from driver download website, it is also not working same problem.

Anonymous said...

Thanks Thanks thanks
God bless You

Jordan said...

This blog post is straight on!

A friend received an HP photosmart C4580 free with the purchase of a laptop. Not needing the printer, he gave it to me. Talk about a white elephant!

After installing it (about 2years ago) I noticed that my machine took a huge nose dive in speed. Realizing it was a function of a motherload of faulty printer drivers, I uninstalled everything related to HP and let the printer collect dust for nearly a year (a glorious year of optimal PC function ;-P)...then I needed to use the scanner. So, I did a custom install, gingerly selecting the bare minimum required to get the scanner working. This was moderately successful...until I traveled and ended up on other networks with other HP printers installed. It seems that this put the fragile HP software back to being a nuisance.

My solution? Uninstall everything and anything having to do with HP...and yes, I will be looking gift printers in the mouth from now on ;-D

Anonymous said...

I just found the same issue with the 'Net Driver HPZ12' service. We use Excel 2007 and Excel 2010 w/ TM1 Perspectices (Cognos addin for Excel). Every time the user launched TM1 it would hang. I finally looked at each svchost and started disabling drivers until I found this one.

bill said...

helpful advises above..

Anonymous said...

Well darn I was here for something else but just learned what I really needed to know.

I was checking out the net Driver HPZ12 Service in Process Explorer to see why it was a Unverified service [ process explorer couldn't verify the files signature]. But my Explorer and desktop hanging issues has been annoying me for ages.

Darn it, I already killed many of HP's useless files on my XP and I noticed many of the files are old anyway; they just stop fixing the problems and put out new printers; with new problems.

Heck I only use the scanner because Ive had problems finding Generic ink that works with this printer correctly w/o errors and Im not paying HP $50 bucks for some darn ink. i have a laser for that, screw color anyway.

I need to just Un-install this hp inkjet printer and leave it for my Linux boot. Darn I never had these problems with my SCSI flatbed scanner; those were the days.

Thanks for the heads up.

I realize this blog is old, but it still applies to many that don't even know it; like me.

And I have a tech background. Still learn something new everyday.

Anonymous said...

Hey, I owe you one.
It helped a lot

Unknown said...

2015 and this driver is still causing Winsock issues.

Disabling the driver(s) on a heavily used TS farm was a big win.

Can only presume the service was installed as part of a printer install before my time.

Unknown said...

2015 and this driver is still causing issues.

Disabling HPZ12 driver(s) on a TS farm a big win.

Can only presume drivers installed as part of a printer install before my time.