how to create differential backup with full backup on every Friday

Robert, welcome to these user forums.

It is fairly easy to do as you ask but it will depend on your computer being powered on / active on each day for this to work correctly, i.e. for the new full backup every Friday.

The first step is to create a new backup task, selecting your source data and destination backup location, then click on Options and select your desired backup scheme, i.e. Incremental or Differential backup.

Next, on the Backup Scheme configuration page, select the option for how many Incremental or Differential backups should be created before a new Full backup is created, so select to create 6 backups then a new full backup in order to have a daily backup with the full backup on a Friday.

Important: If you have limited storage space for the backups, please enable Automatic Cleanup to manage the size of backup data being stored.  I would recommend using "Store no more than X recent version chains" where you need to determine what value X should have based on how much backup space you have available.  A version chain = your 6 incremental or differential backups plus the initial full backup file.  Cleanup only runs when a new version chain has been successfully started with a new full backup, so your backup drive needs to have space to store X version chains plus 1 more full backup.

Finally, on the Schedule options page, set the backup task to run daily, starting on a Friday.

Note: if your computer is unavailable or powered off, then you can click the option to run a missed backup when it is next powered on, but if you miss a day, then the Friday full backup will move to Saturday.

The problem is the Schedule options page.  If I Select Daily there are options for Every, Once a day, or Twice a day.

If I select Weekly then I can select Friday but doesn't that do a backup only once a week not every day?  Or is the selected day when full backups are scheduled and Incremental backups are done in between?

The reason for a full backup on Fridays is a full backup is big and it takes all weekend to backup to the cloud.  The backup just finishes before Monday work start and doesn't then interfere with other normal company internet tasks because the backup is sucking up all the upload bandwidth.  If upload bandwidth was a big as download this wouldn't be such a big deal.  Large upload speed isn't an option with our cities internet providers so my only option is to always have the large backup done on Fridays.

Robert, the options for creating a daily incremental or differential backup cannot be set via the scheduled tab, this is purely for configuring when the backup task will be executed, not what type of task or what options the task will use.

If your backup task will be to the Acronis Cloud (as per your update saying it takes all weekend to do this) then there are no available options to do what you are asking - a Cloud backup will always start with a full backup of the source data but after this, Acronis does a delta comparison to determine what data will be uploaded, so you cannot select to use incremental or differential backups to the cloud.  Also, you cannot configure to create a new full backup every Friday to the Cloud, it doesn't work that way either.

The earlier advice I offered was based on doing a local or network backup to a local NAS, not to the Cloud.

The cloud I'm referring to is my own computer in another offsite location.  I do the backup locally and then copy it offsite.

So the question is how to do a full backup on every Friday and only Fridays and do incremental / differential backups the rest of the week.  I want to do a backup whenever the computer is on but only do full backups on Fridays.  How do I set the schedule to do this.  I know how to setup True Image to do the other parts I just want the schedule set.

Robert, another option might be to run two backup tasks. One task could just do a full backup on Fridays with no increments (for the cloud). The other would be a regular incremental backup.

Yes, there would be a redundant local full backup done, but you could also consider that with the full backup to the cloud every week consider making the incremental backup run with more increments.

The problem with two separate backups, one full only on Fridays and then a second backup full with incremental is that the incrementals are in relation to its own full backup not the one done on Fridays.  So if I don't copys the second full backup which could be done on any day, the incrementals, in case of a fire at work, wouldn't really do me any good since they aren't relative to the Full backups done on Fridays.

I need a full backup on Fridays and incremental in between.  I want to be able to start this i.e. set it up, any day of the week and use all the other auto cleanup functionality already built into to True Image. 

Robert, the other approach for backing up would be to do so to a NAS device where this is in a different physical location but still accessible to your computer, perhaps located in a fireproof cupboard or similar.

Taking this approach would put some distance between the computer drive(s) and the backup location, and depending on the NAS, you may also have further options to mirror the backup from that to another NAS device.

Robert, there is another possibility that I don't recommend but I did a little experimenting and it may work.

The script file for the backup has an option called "rotation count" and is set to the number of increments before doing the full backup. If you were to change that value on Fridays, it could cause a new full backup to be run. You'd need to experiment to make it reliable to where it is only doing the full on Fridays and increments any other time. Yes, you could go into the UI to change it, but perhaps it could be done programmatically on schedule.