CobianSoft

I would begin by changing the installation mode from Service to Application to see if the problem is solved.

Not without a backup no...

Is the Clear archive attribute on the Advanced tab set?

This happens only with "Common folder names" i Windows: Documents and Desktop will always show that name on Explorer even if the names are some others. To solve that you need to exclude the file desktop.ini. Add this file as a mask in your exclusion list.

I find the search function of this forum to be quite limited...

The red flag indicates that the files created by the backup should never be deleted. Just a way to keep some backups safe.

Exactly. This is the way the client has to know what host to connect to.

Interesting to know why it failed on the first try.

You could also delete the history of the backup to force the task to begin from zero.

A differential backup will NEVER clear the archive attribute . An incremental will.