Long story short; about three months ago I wanted to use said program to create a backup of my Windows 10 machine. It failed again and again, and a thorough chkdsk revealed that every single cluster of the external HDD it was writing to was marked bad.
Today I managed to get myself to have a look at it. Interestingly, a little digging with diskpart made me discover that -8MB (yes, negative 8 megabytes) was free for usage. I erased the partition and did a full format, taking about 6,5h. So far I seem to be able to create txt-files on it again, another chkdsk will be done to confirm the disk's functionality.
I now believe Windows 7 legacy Backup raped (most accurate expression) the poor disk's MBR.
tl;dr: Window 7 legacy Backup destroys external harddisks on Windows 10.
Today I managed to get myself to have a look at it. Interestingly, a little digging with diskpart made me discover that -8MB (yes, negative 8 megabytes) was free for usage. I erased the partition and did a full format, taking about 6,5h. So far I seem to be able to create txt-files on it again, another chkdsk will be done to confirm the disk's functionality.
I now believe Windows 7 legacy Backup raped (most accurate expression) the poor disk's MBR.
tl;dr: Window 7 legacy Backup destroys external harddisks on Windows 10.