Thanks for providing the fix! Bluetooth must be On before installing the Bluetooth driver update =I turned Bluetooth On, installed the 21.90.1.1, A07 driver provided on the Dell Support website. When I rebooted, the system it came up in about 30 seconds (normal). I turned Bluetooth Off. When I rebooted the system still came up in about 30 seconds.
In August I installed the Killer AX1650 Bluetooth driver version 21.90.1.1, A07 on my XPS 8930. When I rebooted after the installation, my system was stuck at the Dell logo with the spinning circle of dots for about 15 minutes. Finally the system did come up. I did a System Restore to the restore point created right before the driver installation to fix the slow boot up issue. The driver was rolled back to 21.70.0.3 and the system booted normally.I don't use BT on my system, so I thought I'd just leave it on the older driver version. Unfortunately, the Windows 10 Sept 2020 Update included an Intel Bluetooth driver version 21.90.1.1, A07. After it installed and I rebooted, the system got stuck at the Dell logo for 20 minutes. At this point I powered the system off, booted to the Windows 10 USB Recovery Drive and ran a Startup Repair. The driver was rolled back to 21.70.0.3 and the system booted normally.Yesterday I decided to try a different approach. I turned Bluetooth On, installed the 21.90.1.1, A07 driver provided on the Dell Support website. When I rebooted, the system it came up in about 30 seconds (normal). I turned Bluetooth Off. When I rebooted the system still came up in about 30 seconds.I'm just passing this information along in case someone else runs into the same problem. It seems like there is a possible bug in the driver installation software that requires BT to be On before installation to avoid boot problems.
XPS 8930, Killer AX1650 Bluetooth driver causes slow boot up