Hi Jorge, When I installed QVServer 8.5 x64 had some troubles too, not the message your users recieved, there was anothers, but you set the "Restart the Service" in the "Properties/Recovery" section of the QVServer Services when you install the QVServer?
Something that gave me problems was the original "Working Set Limits [70%, 90%, 10%] of the "Advanced" section of the QVServer, so I´ve change them to [10%, 10%, 10%] and now everything is working fine.
I hope this help you and pardon my english...
I've set Qlikview Server service as usual, I mean, "Restart the Service". I've tried your suggestion about "Working Set Limits" and unfortunatelly those settings haven't worked very well.
Anyway, thanks for your suggestion!
If I find a solution I'll post it here!
Jorge Olimpia - Brazil