Solved Windows 8.1: 100% disk activity, 0KB/S disk I/O intense sl

100% disk activity, 0KB/S disk I/O intense slowdown

My laptop suffers from extreme slowdown during boot and when logged in.

Boot time reaches nearly 15 mins.
The PC becomes extremely laggy and occasionally works but then returns to unresponsiveness.

During boot and while logged in, the hard drive indicator light is always on, even though the hard drive is barely in use.

Safe mode is more responsive with low disk activity as desired however it is still a little laggy.

I have disabled the prefetch, windows search and superfetch services but with the same outcome.

My antivirus is Norton Security 2015 however I have noticed that it does not start on startup, and when manually starting the service, apparently the system was unable to find the specified file.

All folders within the Norton program files x86 location are accessible EXCEPT the Engine folder where file Explorer crashes when attempting access.

I have attempted to keep the virtual memory in "automatically manage..." as well as set a custom size of 6GB initial and 12GB maximum.

I had a similar issue and discovered, after many hours of frustration, that Norton antivirus 2014 was interfering with the boot process. I still haven't been able to fully explain why, but I removed it (using the Norton removal tool downloaded from Norton) and reinstalled. All worked for some weeks but it happened again and again. Same problems each time so, reluctantly, I removed Norton and switched on Defender ( built into 8/8.1). Still using Defender after 9 months and no more problems. For me, Norton carries to much baggage and has too much influence on the way Windows works. Give it a try! Good luck!

Recommend scanning with Malewarebytes, can download from Malwarebytes Anti-Malware Download

some PUPs will squander a computer's resources to a ridiculous extent and you may not realize that they are running, or that they are even installed.

Thank you all for your time.

I believe the issues has been resolved. To anyone who encounters the problem/symptoms I will post the steps that I followed in order to solve the issue. I found it very frustrating as some "fixes" such as disabling the Superfetch and Windows Search services didn't work.

The problem may have been caused by Norton Security 2015 and/or a conflict with Norton and another program or a corrupt folder in Norton/system files.

Procedures I followed:
- Unable to boot into normal Windows due to extreme lag: I booted from a Windows 8.1 Install DVD (mine was 64-bit):
----I selected my language which would then open the setup Window (where it says "Install Now") then clicked "Repair..." in the bottom left corner.
---- Click "Troubleshoot"
---- Click "Advanced Options"
---- Click "Command Prompt"
---- To make Windows boot into safe mode, type the following and press enter in the Command Prompt:
bcdedit /set {current} safeboot minimal

The above will make windows boot in normal safe mode.
bcdedit /set {current} safeboot network

The above will make windows boot in safe mode with networking.


After entering safe mode, there was still some unresponsiveness and lag (though not as much as normal Windows)

Under the assumption that Norton was responsible for the issues, I downloaded the Norton Removal Tool however it would run in the background and would fail to respond.

You can also uninstall Norton by pressing Ctrl-X - Control Panel - View by: Category - Programs (Uninstall a program) however the Norton Removal Tool will be more thorough.

Neither of these worked for me, so I did a chkdsk (Check Disk) by opening File Explorer - This PC - Right click on the hard drive - Properties - "Tools" tab - Error-checking (press Check)

I ticked "Automatically fix file system errors" however you can also tick "Scan for and attempt recovery of bad sectors" for a more thorough disk check by trying to recover and repair the drive (this may take a long time depending on the number of files on your drive).

It will then prompt you to restart then it will perform a disk check and try and fix any problems (this may take a long time but do not interrupt the process).

Once it is done, the computer should then still boot into safe mode.

I left the computer on overnight and, as the disk check finished earlier than I expected, performance in safe mode was much better as everything loaded while I was sleeping.

I ran the Norton Removal Tool, this time it worked successfully and fully removed Norton.

I then opened command prompt as administrator and typed "sfc /scannow" - this will check system files for corruption and will repair them by replacing them with a backup.

I ran Malwarebytes Anti-Malware and performed a full Threat-Scan. No issues were found for me, but it is nice to be completely sure.

Open "Run..." by pressing the Windows logo and R on the keyboard. Type 'msconfig' and hit enter.

Go into the 'Boot Tab' and uncheck 'Safe Boot'.

The computer will prompt you to restart, and it will boot into normal windows.

The performance greatly improved and disk usage dropped to its normal amount.

As Norton was uninstalled there was no real-time protection. You can either use Microsoft's built in Windows Defender or install a 3rd party antivirus (e.g. avast!, Bitdefender Free, AVG Free, Avira Free). I decided to install ESET Smart Security 8 as I had an old giveaway serial.

I then also installed all outstanding Windows updates and rebooted.



If none of the above works (last resorts):

Charms Bar -- Settings -- Change PC Settings -- Update and recovery -- Recovery -- Refresh Install (reinstalls windows but keeps personal files and folders)

Backup all important files/folders to an external hard drive then perform a clean installation of Windows,

System Restore before the symptoms occured or before the installation of Norton.