Can you explain how to do it step by step? it is important to not screw up the blockchain, having to re-sync again would be a nightmare.
Add the following to your bitcoin.conf file. If your bitcoin.conf file does not exist, create it.
Start Bitcoin ABC.
That was easy, the blocks folder is now smaller than the chainstate folder... pretty weird to see
But there is still a problem, when I reopened Bitcoin ABC, the progress bar is 112 hours away, it's stuck at 99.99%, and the other counter on the bottom left of the window says "97.5% Syncing Headers" and it's stuck there... what's happening?