G-Drive with Thunderbolt 3 not working with Time Machine

Ive recently bought a G-Drive with Thunderbolt 3 6TB and connected it to the imac 27’’ 2019. When I connect the mac with the provided G-technology Thunderbolt cable to the Thunderbolt port on the G-drive I get strange behaviour with Time machine. The disks can be seen on the Mac without problems, I can write to it as well. Once Time machine starts backing up it randomly getting errors "cant write backup " and/or disk “disk not ejected properly” .
no errors on disk check found. unmounting re-partition and format ( mac os extended journaled ) didnt help either.
If I connect the same cable to the UBS-C port on the G-drive no problems at all,

Any ideas what this could be ?
Many thanks in advance

The TB interface on the drive could be an issue or the TB cable could be an issue over that interface specifically. Do you have any other TB3 cables you can try?

try resetting the SMC on your imac, worked for me (on a 21" 2019 imac). know, tho, that this drive never spins down; not a good design idea imho…

I had that problem and more. Bought a new 4TB with Thunderbolt 3 specifically to have the Thunderbolt option for my new iMac 21" 2019. The drive was wonky with sleep, file transfer, Time Machine, wouldn’t delete files moved to trash and it locked up the computer more than once to the point of having to unplug everything to crash out. Sometimes it would get really warm while “frozen” in a process. After 3 days of fighting I switched from the supplied Thunderbolt 3 cable to the supplied USB 3C cable. Everything worked fine. Either the cables are bad or the software for Thunderbolt is bad: but I could have bought more TB storage with the “non-Thunderbolt” version of the drive for less money. Seriously considering sending this one back and doing just that.

I’ve tried a new cable , but didn’t work either , had all the issues above. Since plugging in the TB3 cable to the USB C port on the disk it works fine.

I have the same problem with a new MacBook Pro, Intel Core 9, running OS 10.14.4 I initially connected the G-Drive with Thunderbolt 3 to a Thunderbolt port on my MacBook Pro, using the cable provided with the G-Drive. I set up Time Machine. When Time Machine starts, it worked for about 2 minutes, then I got a error message that I did not eject the drive properly. I tried the other Thunderbolt port on the G-Drive. Same error. Interestingly, the MacBook Pro System Report says the G-Drive is connected to the MacBook Pro. But in either case, Disk Utility can’t see it. I thought that perhaps I had a bad cable, so I bought a new official Apple cable. Same problem. Now, using the USB-3 port on the G-Drive Thunderbolt, I have no problems with Time Machine. This leads me to suspect that there is a problem with the G-Drive Thunderbolt or its software. Very disappointing not being able to get the full speed out of this drive.

It is the same speed regardless of connection. The limiting factor is the drive inside, not the interface being used.

If the TB interface is indeed faulty then you can return it to the place of purchase if still within the return period and get a new unit. If it is beyond the store return period you can generate an RMA on our website to get a replacement under warranty. However the performance will be the same over TB or USB.

The problem is that Ive bought the product in the US, during a business trip, because my prime backup disk failed. Now Im back in Europe and on the support page they telling me, that I can only return the product in the country where I’ve bought it.
This doesn’t seem to be real global support.

Same problem. 2018 Mac Mini and 4tb Thurderbolt 3 G-Drive, both brand new. Drive mount fails during sleep with “not properly ejected” error message when computer wakes up. Also has the mount fail when running a sync. Some research suggests that this is common with WD drives on recent Mac OS’s. Fortunately, I have a Seagate desktop drive that doesn’t have this problem (also 1/3 the price). G-Drive has too many issues for such an expense item - so going to return it.

Ive raised a ticket with WD and they opened an RMA for me. After a few emails I did send the drive to the requested HGST address. Today Ive received the replacement drive. All the problems I had before are gone, works fine as expected, but I realised its a refurbished drive ( label on the back ).
Not sure what that means, as long it won’t impact the warranty.
To all the guys reported problems with the drive , please contact WD support , they are very helpful.