Today on of my Vista developing workstations suddenly became very slow, the CPU was almost free and its usage was around 3-5%, the Hard Drive instead was overloaded with work, with its activity at 100% all the time. Trying to do any operation on the system requested 1 or 2 min to open the start menu or display a window.

Restating the system didn’t helped much, so I started to investigate the problem; opening the task manager and then the resource monitor I found out that I have many processes called like svchost.exe (LocalSystemNetworkRestricted) that were reading every files on the system (even the file related to the games I play at night).

So I opened the services management console to find something that could be run using svchost, I looked at every service there and found out that the ‘SuperFetch’ service (‘Ottimizzazione avvio’ in my Italian OS) was launched with this command: svchost.exe -k LocalSystemNetworkRestricted.

I disabled the service and rebooted the machine (I had to perform an hard reset cause the system was still hung reading the files on the disk). After the restart the problem disappeared and the system is back to be responsive.

In the end, it must be a bug of some sort related to the SuperFetch service, cause it ran fine for months without causing any problem.