For faster initial connection times, Tramp stores previous connection properties in a file specified by the user option tramp-persistency-file-name.
The default file name for tramp-persistency-file-name is ~/.emacs.d/tramp.
Tramp reads this file during Emacs startup, and writes to it when exiting Emacs. Delete this file for Tramp to recreate a new one on next Emacs startup.
Set tramp-persistency-file-name to
nil to disable
storing connections persistently.
When Tramp detects a change in the operating system version in a remote host (via the command uname -sr), it flushes all connection related information for that host and creates a new entry.