That is the first reason I do not have anti virus. Been clean for what, 10 years now? Never seen a need to use a program that just slow downs my PC and does nothing.

Tantality

SilverSociopathI have NO idea why.
I started up Minecraft and absolutely EVERYTHING was gone. Vanished.
My worlds, gone. The mods I installed, gone. In fact, Minecraft itself had to reinstall everything. No, there wasn't a power outage or anything that could cause this. Just...gone.
I looked in the .minecraft folder and there's zero trace of everything I had. Luckily, I didn't have any worlds I necessarily cared about on this computer. Despite that, I would like to know why everything vanished.

Anti-virus might have picked it up as a virus (doubt it), virus actually deleted it (doubt it, I don't think it'd specifically target a specific folder, especially minecraft), or your HDD/SSD is failing, and the sector it was saved to was corrupted (Again, I doubt this, but there is a chance it could happen). Though it is strange.

If there was something important in your .minecraft, (Though you said there wasn't, this *might* help others), get a tool that can check for deleted files (Not sure of any good ones) and check to see what happened to it. You may be able to recover it if it hasn't already been over written.

Yea I Agree, whenever I install something from steam it says that it is a virus, so most likely it is your antivirus or firewall

SilverSociopathI have NO idea why.
I started up Minecraft and absolutely EVERYTHING was gone. Vanished.
My worlds, gone. The mods I installed, gone. In fact, Minecraft itself had to reinstall everything. No, there wasn't a power outage or anything that could cause this. Just...gone.
I looked in the .minecraft folder and there's zero trace of everything I had. Luckily, I didn't have any worlds I necessarily cared about on this computer. Despite that, I would like to know why everything vanished.

Anti-virus might have picked it up as a virus (doubt it), virus actually deleted it (doubt it, I don't think it'd specifically target a specific folder, especially minecraft), or your HDD/SSD is failing, and the sector it was saved to was corrupted (Again, I doubt this, but there is a chance it could happen). Though it is strange.

If there was something important in your .minecraft, (Though you said there wasn't, this *might* help others), get a tool that can check for deleted files (Not sure of any good ones) and check to see what happened to it. You may be able to recover it if it hasn't already been over written.

Was there a change in the graphics driver or anything?

Something wiped it, list your anti virus, some programs go Win+X, programs and features uninstall junk. Sometimes my server list gets corrupted or reset but not worlds.