We have received some comments and reports from Beta2 users of version 0.08.82 of slowness of their PCs and lots of hard drive I/O activity from PSANHost.exe.
We are tracing this problem back to an interaction of the new synchronous OnAccess cloud-scan with the BackgroundScan. This interaction seems as it could be the source of the slowness of the system even though we continue investigating it. Basically this occurs under certain circumstances when both scans are consuming the same resource. We’re in the process of redesigning these two scan tasks so they are optimized in the use of critical system resources to avoid simultaneous accesses to common resources.
As a workaround you can disable the BackgroundScan altogether. Disabling this task does not compromise the security level of the PC as the OnAccess scan guarantess the protection of the machine. If you apply this workaround simply make sure to run an OnDemand scan periodically to ensure there are no inactive & latent malicious files in the drive.
To disable the BackgroundScan simply create the following registry entry and reboot the PC:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINESOFTWAREPanda SecurityPanda Service Host]
"BackgroundDisabled"="-"
If you are not used to playing around with the registry, simply download and execute the .REG file in the following file:
http://blog.cloudantivirus.com/wp-content/uploads/2009/07/background_disabled.zip
As we continue investigating this problem, if you are affected by this problem and are able to send us debug information please get in touch with us. Thanks again to everybody for your help 🙂
Tags: architecture, known issues, on-access, workaround
Panda Cloud Antivirus Blog 
July 22, 2009 at 5:09 pm |
Dear Sirs
Yes, I got this situation with continous IO operations of the HDD. This bring temperature of the HDD quite high, but this doesn’t slow down my notebook. Before I’ll switch off the background scan, I could send you debug information but I don’t know how.
July 22, 2009 at 5:42 pm |
Hellow again
I made registry modification with your REG file, the mentioned entry was added and I did reboot. But it’s still about 60 items of PSANHost.exe in system monitor reading my HDD…
July 22, 2009 at 11:41 pm |
Nice feature, quiet work 🙂
July 23, 2009 at 1:27 am |
@Konstantin In the next post I’ll detail how to create dumps and upload them to us. Give me a couple of days please.
@jsn Yes, absolutely! This is exactly how I have it running on my personal machine. Works awesome 🙂
July 31, 2009 at 3:05 am |
My PC had slowed down quite a bit with lots of i/o from psanhost, disabling the background scan worked, thanks.
August 21, 2009 at 6:41 am |
disabling background scan works thx, bur XP security center reports that antivirus is turned OFF ?
August 22, 2009 at 8:29 am |
@Miran
It would if you right clicked on the panda icon and hit “Stop antivirus”, but I don’t see why else. Check the task manager, and if psanhost.exe is there, you’re fine.
August 24, 2009 at 8:36 pm |
Hello, the patch definitely helped with my computer; I stream music off an external hard drive over my wireless network and whenever it would run a background scan the music would stutter (streaming over a windows network drive). Thanks!
September 1, 2009 at 8:55 am |
Came across Beta3 today so I can finally use it on my Win7x64 machine! Thanks for the update. In any case, is there a possibility of excluding certain file types – for instance VHDs (VMware/VPC/HyperV/VirtualBox virtual drives). I am not sure if you are already skipping these; but having it configurable would help a lot.
September 10, 2009 at 1:12 pm |
@Jonathan Dickinson Yes we’re working on adding advanced configuration options for v1.1, including these types of exclusions.
September 28, 2009 at 3:55 pm |
can you please add “disable/enable background scan” feature in next version?
October 6, 2009 at 5:08 pm |
@sina Yes we’ll add this to version 1.1 (the first version after the initial release).
October 7, 2009 at 6:03 am |
If I disable the background scan ( as I have the same issue ) would it continue to be disabled in future releases? Will I need a fix in order to engage the background scan again?
October 7, 2009 at 7:53 am |
@Peter Yes, you’ll simply have to get rid of the registry entry in the future if you want to re-enable it:
[HKEY_LOCAL_MACHINESOFTWARE\\Panda Security\\Panda Service Host]
“BackgroundDisabled”=”-”
October 7, 2009 at 11:43 pm |
Ok, I never play with the registry other than using the occaisional registry cleaner. I suppose I just search for it and delete it.
October 7, 2009 at 11:44 pm |
Also, may I ask how many users are in the cloud?
October 25, 2009 at 6:44 am |
why it’s still not fixed in the current release (8.83)?
October 25, 2009 at 11:21 pm |
@patrick Version 0.08.83 is Beta2 which is where this problem appeared. It’s fixed in Beta3 which will be released later tomorrow. Please check back here to download Beta3 where this issue is completely fixed.
October 26, 2009 at 7:38 am |
When upgrading to Beta3 will it reverse the changes to our registry?
October 26, 2009 at 11:28 am |
@IZZO No, it will maintain them. You’ll have to manually delete the BackgroundScan entry before installing.
November 5, 2009 at 5:00 pm |
I am having the same issue today. Has this been repaired or should I use the registry workaround? Running Windows Vista Home Premium.
November 6, 2009 at 12:32 am |
@Patrick Krug You don’t need the workaround anymore if you have Beta3 (version 0.90) installed. Click on the “?” on the upper right corner and then “About Panda Cloud Antivirus”. If it’s lower than 0.90, browse over to http://www.cloudantivirus.com and download Beta3.
December 26, 2009 at 5:49 pm |
BEfore I was using the beta version of Panda but now I am using Panda Security version 1.00. The problem spoken of still exists even in the ‘stable’ non-beta version. AS we speak psanhost.exe is using up 50 percent of my CPU – this is consistently the app that pushes my computer to 100 percent use. Now, do I really care if my computer is at 100 percent? No, not really except for one SMALL thing – IT BECOMES PRACTICALLY FOR ALL INTENTS AND PURPOSES UNSUSABLE WHEN IT’S LIKE THIS. Is there some way to make PSANHOST behave and be nice to me?