PC Mod safety

game mods?.

if your talking game mods it depends on the site you get em from. the nexus mods recently removed a few gta v mods that contained spyware/malware.
and while that may sound like a reason not to go there and download from them, they were on the case as soon as they knew about em, they banned to uploaders and removed the mods as well as putting a prominent warning on there main page.

would i use the nexus after this? yes and still do.

another good site is mod db. solid comunity of modders although the games that are supported tend to be older for the most part. but still a good source.
 
If you don't really know what you're doing with modding or it's your first time, I would highly suggest looking at some videos that describe the process and walk you through on how to do it. Modding is a very tricky aspect of PC gaming and in order for things to come out right, you need to be fairly strict on how you set up your mods and preferences. You're basically editing the games core files when you mod, so any information on keeping your game backed up and proper installation are undoubtedly necessary.