Both PC and Mac Book cannot detect iXpand Flash Drive

I bought the Ixpand 64gb today and after charging, put it in my MacBook USB port. It recognised the drive and I was able to transfer movie files to it. But as it needed the firmware update to make it compatible with our IOS devices - and I had already updated all of them to IOS 9 - I used a friend’s PC laptop to download the firmware and install it. I was told it was installed successfully.

Now neither my Macbook Pro (running 10.10.5) or our iMac (ditto) will recognise the drive, or mount it. The drive shows as being attached in the system profile, but refuses to show in the Finder or the Disk Utility. I have spent hours looking for a solution but nothing works. 

My system log shows:

“30/09/2015 18:42:38.000 kernel[0]: USBMSC Identifier (non-unique): 0123456789AB 0x781 0xcff0 0x100, 2”

when the drive is inserted. No other messages follow until I remove the device.

It works fine with my ipad now, but that’s no use if I can’t get my computer to see it and transfer my files to it to use with my ipas