scree74
.....so even if I remove the the tick the backup times out 24 hours
Removing the tick is incorrect.
You need to tick the box that says
Don't timeout full backup sessions
I think the trick is to allow a scheduled backup to start (say on Friday night at 8pm) and then after the backup has started, go into server manager (at 8:10pm) & disable the backup.
That way the backup program will NOT try to run another backup in 24 hours time (at 8pm on Saturday) which would as you say cancel the running backup & delete all the files on the backup disk tmp location.
This will allow the full backup job to complete, however long it takes whether 30 hrs, 36 hrs, 48 hrs or even 72 hrs (because you have told the system to NOT time out full backups).
When, in a day or two or three, you have a first full backup complete and you receive the email message to admin advising of a successful completion, you can re-enable the backup job.
Then I suggest you change the settings to daily incrementals for whatever time period you feel comfortable eg you can have 1 backup job with 365 daily incrementals, that way you only do a full backup once a year. In your case the cycle you chose will be governed by how often you want to perform this manual procedure to get a full backup completed.
If the daily incrementals do not complete in 24 hrs then they will be automatically postponed, & should recommence from the same point on the next scheduled backup.
I would imagine though that most incrementals will only need to backup a small amount of changed data, so the backup time, should be relatively quick eg a few minutes or an hour or 2. It really depends on how much data changes on your server every day & how big the changed files are.
Also if you use a high(est) compression rate, then your processor may be taking a long time to compress the data, & that could be the reason your full backups are taking so long (over 24 hours). In that case use a medium or lower level of compression setting.
That's why in my earlier post I suggested you should find out what is causing these long backup times & fix it, as it does not sound right to me.
PS I just thought of another reason why the files in your backup tmp location are being deleted.
It may be that the backup disk does not have enough space on it to save the tmp files and copy them to the main backup folder.
In that case the backup will fail, leaving the stranded files in the tmp location.
The next time the backup runs, the first thing it will do is delete the tmp files & then start again with a new backup.
The backup location needs to have more than twice the resultant backup data file size available.