cMP 5,1 (flashed) running High Sierra with recently installed BT/wifi upgrade PCIe card (Broadcom) w/external antenna. The old (factory) BT card, which had quit, has been removed and replaced by USB dongle. After installing the new card around a month ago, all devices, including Apple keyboard and trackpad, Avantree BT headphones and a Crasher external speaker worked fine. In the past few days the headphones and external speaker have been failing to connect. Thinking it might be that the headphones could be confused by the presence of my MacBook Pro, which I also connect them to without problem, I deleted the headphones and speaker from my BT system prefs. Now the cMP does not pick them up at all. Keyboard and mouse are still working fine, so the problem does not seem to be with the BT/wifi card. How can I add devices to BT prefs if the Mac does not initially want to see them? (BT headphones still work with my MacBook Pro, BTW.) Turning BT off and back on does not help. Apparently there is something about these two third party devices that doesn't play well with Macs when connecting. I just ran a check on the BT card in TechTool Pro 11 and found the following information: Manufacturer: Broadcom BT version: 4.1 (0X7) Firmware version: v114 c4546 Discoverable: Off Connectable: Yes I was surprised to see the discoverable attribute was turned off and it seems to be a likely culprit. The problem may actually be that the devices can't find the Mac rather than vice versa, so changing the discoverable BT attribute to "on" might solve it. I have used an app called Bluetooth Explorer but version I have does not work with High Sierra. Does this seem likely to be the problem and if so, where do I get BT explorer for High Sierra?