Thanks. I read through that article but it does not apply in this case. All the folders are linked correctly, yet the files within the folder are not.
For example, Lightroom is looking for a file named "expensive-sliders-2.jpg". When I click the "!" it takes me to the correct folder but the file inside is named "expensive-sliders.jpg". Now imagine this is happening 851 times. I coming up empty on ways to rename the catalog files in a batch.
The -2 can also occur when you export to the same location and have checked the option to add the exported images to your catalog. I'm nor sure what happened in your case.
However, I unfortunately don't see any other way than re-link every single file.
So I ended up manually relinking all 800+ images. It was boring as heck, but done over three sessions really didnt take too much effort.
I still can't figure what caused this, but I sure hope it doesn't happen again. Thanks for all your replies!