I have been having this problem for a while on Win2003 server. It seems the mapped drive eventually is dropped if there is no activity on the drive for a while. One thing that seemed to help is to turn this timeout off in windows using the following:
net config server /autodisconnect:-1
I am not sure if this works on Win 7,8,10.
Simply put this inside a bat or cmd file and have it run when the computer boots.
I still get this probably occassionally but this seems to have reduced it a bit.
It would, however, be really great if the Idrive people could solve this once and for all as it is quite annoying.
Gary