pcManFM has a bug that it does not save the password for (in y case Samba access)
On can click on ‘Save forever’ forever; it’s no use.
Install another File manager like Dolphin.
Open the Samba directory, fill in username and pasword and tlee Dolphin to save the password.
When you open pcManFM the next time you won’t need to fill out username and password.
I don’t know.