Media Write Error (84)

Something sounds really wrong - if all you did was to add the diff schedule it makes no sense why your earlier backups with a retention of 1 month have dissapeared

You wont get rid of the Journal message as accelerator always checks to see if it can use it - but in view of what has gone on i would be inclined to create a new policy from scratch (do not copy the existing one) with all of the streams defined and you daily / weekly/ monthly schedules and run that one (disabling the other one)

The first time it runs it will create a new track log (as it is based on policy name) and run a "real" full backup.

The next full runs will use accelerator and incrementals will refer to the track log to assist them

See if that sorts it out for you as it sounds like something is really wrong somewhere

The only other thing i can think is that someone has expired some of the backups so removing the missing streams and causing accelerator not to work - but if you only actually see 2 jobs that that could not be the case either

Try the new policy and see how that goes over a week or two