I took out a hard disc from my Xtreamer and inserted it into a disc enclosure as an external disc (to be used as a backup disc).
My computer sees it as Xtreamer (G) and does not allow me to format or even to look at the contents. The messages are:
1)when trying to explore the disc:
G:/ is not accessible
2)when trying to format it:
"you have not sufficient rights to perform this operation"
I guess that the fact that it was in a Xtreamer causes all these problems.
More about :external disc recognized accessible xtreamer
Problem solved; today I tried the very same actions as yesterday and everything worked perfectly, to my surprise. I have not a clue what was the problem.
Thanks to all the nice people who tried to help!