Hi i know this post is old but i was searching for solutions because I had the same issue. I manage to fix the issue following these steps:
When moving the files from MAC to PC first you have to upload your mods folder to an online storage site. I used a 30day free trial of drop box because it allows me to upload up to 10TB (10,000gb) and i had 96gb in my mods folder. google drive only lets you upload 15gb.
Once i uploaded it to drop box, it split the file into two, the original file and a copy of the file with a "." in front of it.
After i redownloaded the folder from dropbox i deleted the "." copy of the file and put the downloaded folder into my mods folder and the game worked normally. I also deleted the ".ds store" file which is a mac file.
ps. if i tried moving the mac file via sd card to my pc then the "." copy file didnt show up and my game would show the error.
pps. in case you only have the files on an sd or usb, you can upload the files to dropbox via an sd card you dont have to upload the files from your mac for it to split into two files.
Hopefully this helps someone else in the future because this was my last hope before i was deciding to just use the mod manager to go 1 by 1 and just redownload 96gbs of mods
THANK YOU!!! This worked for me!! I was trying everything else!
