I have looked for any solutions for this problem, and it is a huge problem I'm having with the latest upgrade. I saw another user has had the same issue and posted it on the apple forum here. https://discussions.apple.com/thread/8111053?start=0&tstart=0
But there's no answer for it.
Since upgrading to High Sierra, every time I close an application it forgets all the passwords I have saved in that application. Coda, Chrome, whatever it may be.
All my FTP password details stored on Coda, get forgotten every single time it's closed, same for Chrome. My gmail accounts, toggl, any site which would keep you logged in, doesn't and forgets entirely.
I have tried checking my Keychain Access, it looks okay I think? If anyone else is having this problem or knows a solution I'd be very grateful!