Iphone backup with iTunes on Win11 not possible

Some times ago I tried to shift iTunes backup of my Iphone from C: to another drive. Something went wrong. When I try to make a new backup I get message "backup error because backup is corrupted, pls. delete the backup". If I go to device settings in iTunes there is no backup to be deleted. Also in the corresponding folder on C: drive there is no backup. If I use 3.rd party tools I see that expected folder for backups is E:\Iphone_backup\backup". Interesting is that " sign at the end. Changing iTunes folder for backups with 3rd party tool eg. to initial value is also not working. How can I start backups from scratch so that I Tunes is not looking for old backups but is using initial values. How to delete that E:\Iphone_backup\backup" setting. Reinstalling iTunes doesn't help.