Thank you. It is working properly.

When defining a paragraph style, the Line spacing field takes no value other than Single. Lines field only 1.
Any value can be entered during normal paragraph formatting (out of style).

MyInfo 8.3.1

Updating MyInfo [7836] did not help.
But I noticed when the error occurs.
The backup problem only occurs for password protected files.
After removing the protection, the copy executes correctly. After re-securing, the error occurs again.

Normal.

After installing Myinfo 8, I receive a message:
"Backup failed. Unable to backup: jacek (On 2023-04-01 13.37).mbk in ..."
In the same directory in which Myinfo 7 correctly performs a backup.