New WD my passport 4 tb - cannot reformat, partition or add time machine

WD External Drives External Drives for Mac
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Hi guys, I bought a WD my passport 4 tb and can’t re-format, partition or backup with time machine. When trying to erase, it says erase process has failed as it could not unmount the disk. Time Machine won’t backup as it says it needs to be in the OS Extended (Journaled) format - my drive is in the OS X extended (journaled) format and there isn’t an option for just OS. Any guidance would be great thanks!