Hi there,
I’ve found other issues regarding this (this among them), but nothing that exactly pertained to my issue.
On MacOS, updating to 4173 (after finally purchasing a license) destroyed my session file, completely overwriting even the one in the Sublime 3 folder with blank defaults. My last backup is 4 months old, which is… honestly not great.
I guess it’s too late to recover anything? According to the search, this has happened at least once before. I made full copies of my library folders. Are there any logs I can provide to prevent this from happening in the future?