BTStackServer.exe
(Widcomm)
Widcomms Bluetooth Stack COM Server. Background COM server task that is essential to the proper running of the other programs within Widcomms Bluetooth software, such as BTTRAY below.
Recommendation :
Leave alone. Note, however, that we have had reports of crashes needing a reboot for Bluetooth to work so check the device manufacturer website in our Drivers section for more recent drivers.