Thank you for your support.
Please see my answer below
How are you uploading files?
From windows explorer standard, mapping a network unit. With copy and paste.
What operating system or mobile device and version are you using?
It is a PC with Windows 7
Are you using WD Access, Windows SMB, macOS AFP or SMB, some third party software such as FileZilla or WinSCP? Or are you using MyCloud.com?
No when hangs, we are using only windows copy and paste files.
Cloud Service: OFF
Dashboard Cloud Access: OFF
Energy Saver: Drive Sleep: ON
Do you have Twonky DLNA, iTunes Server and Cloud Access turned ON?
I have only Twonky DLNA turned ON, but there is not activity of DLNA
Any 3rd party apps installed?
Only ones that come with the product and all are OFF.
What router are you using?
When Mirror hangs, all the other elements in the network work well as ever.
Is the mirror and computer on the same LAN?
Yes. Computer is in 192.168.0.20 and mirror is 192.168.0.5
Both has dynamic IP fixed by the router by MAC
Is the computer hard wired to the router or wifi?
All are hard wired connected to LAN
What capacity is the mirror?
Mirror has 2 hard disks of 4 TB in mirror configuration. Same that came with Mirror.
Is it Mirror or Mirror Gen2?
It is Mirror: P/N: WD8ZVM0080JWT-20
Is it still in RAID1 or has it been changed to JBOD (RAID0)?
It is still in RAID1 configuration
RAID Volume: Volume_1 RAID 1 3.99 TB Good
As additional information:
When Mirror hangs the upper green led of Ethernet port is blinking and lower green led is fixed green.