General

@sirkibble: I turned off BTS, Window Search, and Super fetch. My problem did not resolve. Virus scans showed nothing, malware-byte showed nothing, and ccleaner wiped out all useless stuff. I'm thinking I need to do what burning said; back up my data, and reinstall win 10.

@burning: Thanks, I'll consider that. I thought I was going to have buy a new hard drive asap.

@xdwow2:

If the problem cannot be determined, there is a last resort that's free. Backup your data and reinstall Windows. The procedure will essentially delete everything from your hard drive and rebuild Windows from scratch.

http://windows.microsoft.com/en-us/windows-10/windows-10-recovery-options

@vivabasura: At the moment I thinking my HDD could be somehow damage. Window's built in status check says nothing is wrong with it, but it could be I need a new HDD. Luckily it's replaceable on my laptop but it's kinda pricey.

@xdwow2: open task admin and then click disc tab to see which app is taking most space... I get this too often, its ''SuperFetch'' under some ''Host service'' what causes the trouble. just click it and kill

ive had this problem since i upgraded to windows 10, i highly doubt its caused by malware or virus like most say in this thread
its pretty much a w10 thing and theres various tutorials around to fix it, i tried 2 and none worked but in the end i didnt really mind because though it says your drive is at 100% usage very often theres no performance problem at all, its just a display error
your lag must be because of something else, i have 0 lag and my disk usage becomes 100% for doing anything

@burning: Scan detected nothing, and deleting the nexon softwares did nothing as well.

@xdwow2:

Well there was the monthly Windows update earlier this week (second Tuesday of every month.)

Since you're going to uninstall the Nexon Launcher anyways, I'll wait to see your report on the result.

@burning: Oh, I only have the launcher because I wanted to play combat arms, which doesn't work cuz of their EU + Global BS. But I installed this about a week ago, there was no problem then. This started like 2 days ago after I restarted my PC as well. Anyways I'm waiting to see what this anti-virus would detect, and in the mean time I might as well uninstall CA since it doesn't even work anyways.

@xdwow2:

The Nexon Launcher by default is always running. In addition, Maplestory may have installed Pando Media Booster which if running, will upload data from your computer to other clients. Pando is completely unnecessary and can be uninstalled since Nexon now uses a new downloader. It may not be installed as I can't quickly check for myself since it has been a long time since I had to reinstall Maplestory, but it was at times reported as a cause of computer slowdown here on Basil.

@burning: After double checking, it seems I do have windows defender. I could do a scan, and see if any viruses are present. As for anything I installed recently, that would be nexon launcher. But I don't see how that could create an issue with my disk.

Anyways, back to windows defender. I don't think it's a very solid anti-virus considering it's free, but it's worth a shot.

Sudden and unwanted high disk usage as you describe is most commonly caused by some types of malware and viruses. However, it is not uncommon for people who experience this problem to "forget" about something they installed recently. Some software can be unexpectedly bloated even for just a moment such as game update clients like Steam and Battle.net.

Note, Malwarebytes is not intended to replace an antivirus that provides continuous live protection. Depending on which version of Windows you have, at least have either Microsoft Security Essentials or Windows Defender since they're free courtesy of Microsoft.

Recommended that you get an antivirus.

Based on this list: http://www.av-comparatives.org/wp-content/uploads/2016/06/avc_factsheet2016_05.pdf

Free ones such as AVG, Avast and Avira will do the trick (or if you're willing to shell out money, something like Bitdefender or Kaspersky will be good, although a lot of free ones come close to doing the job anyways but up to you)

What are the specs on your computer?

@xdwow2: norton antivirus and symantec are both really good, (symantec is better imo), if you google free trial you can get one for windows 10 i think, mackeeper is terrible (although its for mac anyway), some antivirus programs actually install viruses so it can remove them, although i doubt mackeeper is one of them

@bearsandlions: I tried ccleaner to remove any temp files my PC might over produced, and malware-byte to remove any malware. I don't have an anti-virus tho.

ive been getting the same thing for a while, i suspect someone's been phishing

sometimes it happens when you have a virus or some third party monitoring your online activities