I've been playing on my laptop, but today when I load PoE, it doesn't see any of my saves. So, after uninstalling/re-installing and some other messing around, none of which worked, I tried it on my desktop: perfect. Saves are there and I play for a bit. Then I notice the game updating. Reload the game, no saves.

Same, wtf ?!

SOLVED:

You can roll back to the previous version inside GOG Galaxy app (on PC anyway) under Manage Installation --> Configure...

Once I rolled back versions, it's game on.

Previous version flagged savegames as if they were made with DLCs installed, so if you don't have the DLCs, new version won't load them.

Either contact Obsidian for support (they should resolve this quicky because it has become a known issue)

or

Follow some guy's advice about how to manually edit your existing savegames so they appear again in the latest version. Go to PoE forum on Steam and look for topic "Saves are missing after today's update ".