I bought a new Mac Air M1 and I can not find out how to stop Time Machine to erase the content of my external drive.
I tried formatting the "container" as the old HFS+ format as explained in Steve Sande's post BUT it does not work.
format drive as APFS in Disk Utility
then select "container" & reformat as MacOS Extended Journaled (HFS+)
copy some files onto the external usb drive 2TB
ask TM to backup... it wants to erase the content of the drive.
I have always used TM to share external drive with other data... how can I do the same on Ventura?