[NAME]  Two possibilities to consider, and you may need both of them... 1. Some Windows Updates can't be installed when Fast Startup is enabled in Win 10. When you boot up, PC tries to install them but can't, so eventually gives up and boots to the desktop. Try disabling Fast Startup in Win 10 and see if that solves the problem: Be patient at #9 because some updates may have to be installed. When you get back to the desktop, you can re-enable Fast Startup because it will make future boots noticeably faster than when it's disabled. Now do another full power off shutdown, not a restart, and see if the boot speed is improved. NOTE: If the problem recurs in next day or so, it's possible some additional updates are needed, so disable Fast Startup again and then re-enable it again when you get back to the desktop. 2. Did you recently get an update for the XPS 8930 Realtek audio driver, either via Dell Update, Dell SupportAssist, or via Windows Update? Realtek driver v6.0.9205.1 is causing slow booting on the XPS 8930. Open Device Manager and if that driver version is listed for Realtek audio, click the driver roll-back button and roll back to the previously installed version, which might be v9107.1 or v8248. Dell is aware and we're awaiting a fix...NOTES: Good idea to manually set a System Restore point before rolling the driver back, to be safe. If the roll-back button is grayed out, manually download Realtek driver v8248 and install it, after setting a Restore point. (There's no Dell link for v9107.1, which is newer than v8248.)  Regardless of which driver gets (re)installed, you will have to reconfigure Waves Maxx Audio for your specific audio output again.
I bought my 8930 in 2018. It has been running slow for a while, so I ran the Dell site diagnostics (everything checked-out OK) and then flashed the BIOS to update it to the latest version. Though a little faster, the Dell intro screen still spins for about 99-100 seconds before Windows 10 Pro starts-up. Any idea what else I can try? Here are the system specs: Processor: Intel i7-8700 @ 3.20GHz 3192 MHz, 6 Core, 12 Logical Processors BIOS Ver.: 1.1.18 9/6/2021 SMBIOS Ver.: 3.1 BIO Mode: UEFI RAM: 32GB  
XPS 8930, slow BIOS