Not recommended, recurring problems

Hello There,
I have the plate approximately in December for use as a Time Machine on Imac.
Initially, the backup worked great, after 3 months was the first time the message: not poss assurance. Disk read-only. That I managed with various test / diagnosis and Formattierungsversuchen again.
After this outbreak warning symptoms but meanwhile appeared in the 1-2 month distance yet 2 times, I decided to drive to return.

My clear verdict: not recommended!