I've updated to R&R 4.5 on win 7 home premium and I constantly get the error of "R&R is unable to back the file .... because it is either in use by another application or corrupted". I have 3 options to choose from "Retry", "Skip" and "cancel". there's no open application. computer is just rebooted. this is the first back up on R&R 4.5 on an external USB drive, which is just formatted and empty with 150GB. My thinkpad hard is 160GB with 59GB of free space.
When I select "Retry" the file is being backed up instantly but will hit another one constantly.
R&R 4.3 was working just fine before.
This situation is most likely caused by an installed anti-virus software.
Try disabling the AV software while you are making a backup.