External HDD disconnect for security?

Some of the methods suggested are applicable if the external disk is only used for Macrium backups. But in many cases the disk is used for both "system" (Macrium) backups, and data backups, which are done with a different program. In these cases, these procedures do not apply.

The data backups are much more important, the system can always be restored one way or another. I backup the data ten times more frequently than I backup the system.

 

Im frequently syncronizing my internal drives/SSDs with three external drives (2,5 inch). But then i immediately disconnecting
all backup drives from my machines.