My Book 8TB is constantly Unmounting and mounting

My 1 year old My Book 8TB USB 3 connected to my iMacPro is after zending 6 TB of data (to backup my Pegasus) Is now constantly mounting and unmounting. Can’t get any file of to put it back, what is going on?
I have 2 other 8 TB WD My Book’s and they don’t give any problem. Tested them also, with same cable and power supply.

Thanks in advance for any suggestion

Sjoerd de Vries
The Netherlands

I have exactly the same problem. The disk mounts sometimes and sometimes not. Cannot mount the disk with disk utility either. Is there any solution to this problem or do I have to replace the disk because I still have a warranty, Please i f someone can help

Something ‘strange’ happend. For testing I installed demo of DriveX. For use of external disk there must someting else installed whoch DriveX did. I rebooted the machine (which I have done several times before) And the drive mounted coorectly Test with DriveX did not show any error. For now I transfer a 40 GB and a 56 GB file (card archiev’s made with FCPX) and no errors, pfff
Wil test more, now he is copying 4.5 TB of data

And again he is loosing connection, not so many as before but he is still disconnecting and connecting.

I unchecked “put hard disks to sleep when possible” in Energy Saver system preference. That has helped the mounting / unmounting issue for me. Sounds silly but another reason I had issues mounting the disk was because AC power plug had come loose and I didn’t notice. :man_facepalming: