Quick and short, hope it helps.
I was wanting to play POE and had a copy a few months old saved for backup. This will get you back running and the updater will correctly only need to download the newest stuff since your backup and not the entire game again. If it did update this would be a good time to backup the new Content.ggpk again.
BTW to backup Path of Exile all you need to do is save one file Content.ggpk
Instructions on Windows 10, to reinstall backup which should be a single file Content.ggpk read below
First thing download the PC installer, install it to add the launcher/updater. https://www.pathofexile.com/download
Now open launcher to setup folders, after it ends close.
Browse to location C:\Program Files (x86)\Grinding Gear Games\Path of Exile\
Place your backup of Content.ggpk into the correct folder, copy/replace file.
Should look like this below.
C:\Program Files (x86)\Grinding Gear Games\Path of Exile\Content.ggpk
Run launcher again it may have updates, no need to download entire game.
Press launch and play POE!
