save-place-forget-unreadable-files

save-place-forget-unreadable-files is a variable defined in `saveplace.el'.
Its value is

t

Documentation:
Non-nil means forget place in unreadable files.

The filenames in `save-place-alist' that do not match
`save-place-skip-check-regexp' are filtered through
`file-readable-p'. If nil, their alist entries are removed.

You may do this anytime by calling the complementary function,
`save-place-forget-unreadable-files'. When this option is turned on,
this happens automatically before saving `save-place-alist' to
`save-place-file'.

You can customize this variable.