Hi. Thanks for getting back to me. The single drive is connected directly to the motherboard sata conector and its a mehanical drive 4tb. I also have 2 ssd drives that are connected to the sata on the motherboard. one ssd for app-data , another for media storage, and an nmve cache drive all single drives formated to brtfs and xfs and i have no problems with them no data loss. There are no power spliters like molex to sata. So i have tried out several 1 to 4 tb drives that are older but known good drives tested with hard disk sentinel all are 100%. I agree, i think it is a hardware problem by the faults i am having, but i have replaced everything in the chain- sata port-sata cable-hdd-difrent power cable port several times and multiple hdd. Once you replace everything in the chain for me it looks like a software problem. Now i have downgraded the os to 7.2.2 and it seems to work the drive is taking in the data and the data is browsable over the network and keeps its integrity. I am rebuilding the media drive now again. PS.-- The problem i had with the drive was the data files where visible, but when you access them or try to open you cant reed it or copy it. So to not lose my mind i will also try an ssd on the same port -cable and power and rebuild the drive and i will se how it goes. I have experience with windows 2012 server and freenas and when i had a problem similar to this it turned to be a problem with the update......mostly a software problem due to the combination of used hardware. Thanks for taking the time......