Hi ReNNo_BiH,

Thanks for posting.  Apologies that your system is not performing as you expected.

Please perform a systems diagnostics by either going to F12 at boot or by using Support Assist.  Make a note of any errors and post back.  Another thing to try is go to Device Manager and look at the properties for the Bluetooth Device.  There is an Events tab which my show what that device is doing.  It is a small window so make sure and scroll to see the entire listing and select a particular entry to get details.

The Event Viewer may also have some type of entry related to events surrounding the disconnects.

Just for testing, if you are in an area with other Bluetooth devices you might try putting them on airplane mode to shut off those radios to avoid any interference.

Here is some information from the Dell knowledge base you may find helpful:

Guide For Pairing and Troubleshooting Dell Bluetooth Keyboards and Mouse

Hi iHylander,

Thanks for posting this old thread.  Apologies that your system is not performing as expected.

Here is information from the Dell knowledge base you may find helpful:

Bluetooth Troubleshooting and Usage Guide 

If the system is under warranty, please contact me privately. Be sure to include your personal information (name, address, telephone, email) and your computer's service tag number in your message. Thanks.

If there is no warranty, then you could contact our Out of Warranty team to get a quote for a paid service request - http://dell.to/1vnT6CQ

I may have  just experienced the  same thing; in my case with an XPS 13 9370, and the Dell KM717 and Dell WM527 mouse. One moment I was using the mouse, next moment the pointer stopped moving with it, and the keyboard was dead too. Check my bluetooth indicator... oh, it's not there. Check bluetooth settings, it shows no bluetooth interface present, and helpfully suggests I plug in a USB one. Reboot, twice, to no effect.

All this happened in Linux (Ubuntu 18.04), which is my primary OS for using this machine. So then I rebooted into Windows, where it was quickly obvious that it too couldn't see any trace of a bluetooth interface in the machine. SupportAssist showed a fully successful hardware test had just happened, and it could see nothing wrong, but also, when I went to try to choose what hardware to test, bluetooth wasn't an option... of course because as far as it's concerned, the machine has no bluetooth interface to test. Microsoft's bluetooth troubleshooter also ended at the first screen as it too couldn't see a bluetooth interface.

I ran all updates, which as I don't use Windows very often took a while, and included the latest feature update to 1803. No difference to bluetooth, but by that time I'd found this thread.  So when all the updates had completed and made no difference, I tried your procedure: Into the bios,  it shows bluetooth adapter is enabled, so I disabled, clicked Apply, then enabled, clicked Apply again, and for good measure switched off the settings for whether wifi and/or bluetooth respond to the wireless switch (I don't think there is one), and booted back into Windows, where bluetooth immediately showed itself present and I was able to connect my devices and ... more than an hour later it's still working.

I haven't tried it in Linux again yet. I bet it works as before.

But the only thing I can think of that I've done lately that might be relevant: I, in common with a number of Linux users of Dell laptops, have been having problems with suspend, specifically that an awful lot of battery life seems to be consumed while in suspend, we often pull the laptop out of the bag to find it warm, even, with fans running, and tens of percentage points lower in battery life than when the lid was shut not that long ago.

I had just today tried a fix, detailed here. The accepted answer, not mine which didn't do anything much. The accepted answer amounts to disabling "s2idle" in favour of "deep" sleep mode. This appears to be another long-lived issue, and for instance the Linux kernel apparently has a blacklist entry for the 9360 that prevents s2idle working on it, but presumably the 9370 is too new for that to have appeared in the same blacklist. Anyway, that fix appears to have worked, in that a two hour lid-down sleep took hardly any battery life, which is what we expect.

The bluetooth didn't fail immediately on waking up. That would be too obvious! After the test I used the machine for another hour or so and then the bluetooth interface vanished. That's long enough that it doesn't sound like it would be relevant... but it's the only thing I've done to it lately that sounds even a little bit relevant, and after all it does mean the power state of devices gets changed...

So basically I'm waiting for it to fail again... But I think we can say with some confidence that it has nothing to do with Windows drivers.

Check out the solution by @Rowzee "I went to 'add / remove programs' and towards the end found WIDCOMM bluetooth driver. I removed it and system has been fine ever since."

Worked for me.

https://www.dell.com/community/XPS/Unable-to-start-the-bluetooth-stack-service/m-p/5764595#M4702

This was the only solution I ever found so far.

Bluetooth dropping issue is really annoying, and happens very often to me.

It even makes me more **bleep** off if I had to go BIOS and modify option in it every time.

Aren't they Dell or Killer Network supposed to reveal the issue openly and deal with it?

Same problem here. But there's no WIDCOMM installed so I can't bark up that tree. A restart usually solves my issue for now. It was almost at the same moment my warranty expired (coincidence I'm sure but it cut short my options), when I received a system message saying the Bluetooth adaptor driver was disabled due to abnormal activity and it's been flacky, on-off, ever since.

The wireless has also been unreliable on this system. Great computer but it's a real shame to see the same issues popping up time and again without (actual) answers. One would could almost conclude that there isn't an answer. That maybe the Bluetooth solution is a failure on this system?

I think maybe an external Bluetooth adaptor would solve the issue (possibly on a USB hub). They're pretty affordable these days. Although not elegant of course but I am really bored with reading ghosts of solutions about an issue that should not exist in the first place.

FWIW

This same thing has happened to me several times now as well, and like many others I don't have the WIDCOMM drivers installed. The first time it happened a restart solved it, the second time that didn't work and Dell Support spent almost 2 hours trying to fix it with updates and drivers etc. The solution they came up with that worked was to go into the BIOS (f12 on start) and uncheck/disable the Bluetooth Device (in Wireless) then restart and re-enable. This just worked for me again.

This seems to be a fairly common problem that Dell should fix.

I have been having the same problems with my XPS 9370. Bluetooth stops working, disappears, appears as "turned off" for no discernible reason. I had support fix it about five times. They fix it but then it starts happening again a day or so later. 

Frankly at this point I've given up. I don't even use bluetooth anymore because I simply can't rely on it. And that's a problem with a $1700 machine. My $800 HP laptop was a POS but at least it always worked. 

Honestly this is the main reason I would never recommend this laptop. Many, many people hate the Killer card they ship it with. It's either the card or the drivers. One way or another Dell needs to clean this up. 

Has anyone tried just using stock windows drivers? I wonder if that would work. Though I have no idea how to keep the laptop from updating itself back to the Killer drivers. 

In the same boat, with an XPS 15 9550. The ability to toggle Bluetooth disappears about half the time I resume my laptop from sleep. Super frustrating that I have to reboot it to get Bluetooth back, which means having to load up my entire work space again (open browser tabs, files, etc.)

No WIDCOMM driver that I can remove, and nothing looks out of the ordinary in the BIOS, either. 

Also keeps on forgetting my mouse (a Logitech MX Master Pro 2S) and I have to re-pair it, but I can't even remove all of the older paired versions it's stored.