Does external HDD's loose its written data or its free unused data?

dimitrimk

Commendable
Aug 13, 2016
2
0
1,510
Hello everyone, my first post on this forum.
Had a problematic that i couldn't find the answer, last year i bought an external HDD, WD Elements 500gb, i stored some photos and documents in it last year and for the first time since then i opened it last month to find some documents, now i plan to store some stuff again in it, another bunch of photos. When i was buying the External HDD i done a research of how storage looses its memory over the years:
http://www.extremetech.com/computing/170748-how-long-do-hard-drives-actually-live-for

BUT, does it loose its written memory or its unused memory?