Nightly

I suppose for that reason it was not visible - because avsda.dll is dynamic. So, after restarting I disabled on demand, Mail and Webguard services. I was a little bit late - Svchost started to hang up. I killed the process. During the 10 hours, there was no sign of highcpu usage. after 10 hours, started Webguard, and Mailguard. for several minutes it was ok. I turned off them and turned on On demand scanner, just after it Svchost bumped again to 100%. Which tells me that with 99% probability the issue is because of Ondemand scanner.

I am so thankful to you for your assistance on this. As you mentioned about dynamic libraries - actually avsda.dll is Dynamic-link library, maybe for that reason it is not seen in Xperf trace. I will try to make sure this by disabling AntiVir on the next start.

It has been sent.

OK, so, disabling those services, didn't help - it is still using CPU as high possible (Sometimes 1 core, sometimes both of them ) As I indicated before, 90% when I click to thread information "SVCHOST" get killed by itself . This time I could see againg "ntdll.dll" though it was killed. I tried to access "Stack" I got an error "Error accessing thread".

It has been sent to you Update 1 And also interesting point is, when I click to "Threads" for this process in Process Explorer the Svchost process shuts down silently without any error. Update 2: It seems found useful information about this particular issue: the command line is -k netsvcs. I stopped and disabled services SENS , BITS . Though stopping this services didn't kill the Svchost process, I will check the result after restart. Hope this helps

I've already installed Symbols and I also realized that it shows only question marks instead of names. But this issue was on some threads including this one. And as you see below, while symbols are loaded it shows up some thread names, but when it is not loaded, then none of the thread names are shown... Symbols are loaded: Symbols are not loaded:

Thank you. I've read and did it. But unfortunately no useful information I could see on this data. What do you think about it?

I've newly installed same Vista Ultimate X86 to my new Hard Drive. It is not first install - because I've done it 3-4 times in the last 4 days. The last time laptop wouldn't go sleep mode. I couldn't find any solution for this so at last decided to reinstall the system. On this install everything was OK, until the next day - when I discovered that Svchost.exe uses 100% CPU. (I have two cores, and process uses 100% of one Core) In CMD Tasklist command it gave N/A about this particular SVCHOST process. Also looked up in used modules by this process.Basing on this, I suspect Avira. But I checked also another Svchost processes and found Avira is also in used modules of Svchost PID:2560, 1188, 1168 and some others (But not in all of them) Here is also PE Threads information. So, what is your conlusion about this issue?